Re: c question
- use a matrix is faster than use a linked list? For what? For insertion and deletion no - linked list is faster. For sequential access they are the same speed (forgetting look-ahead caching). For random access matrix is faster. ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question
On Fri, Apr 23, 2010 at 06:18:46PM +0300, Eitan Adler wrote: - use a matrix is faster than use a linked list? For what? For insertion and deletion no - linked list is faster. For sequential access they are the same speed (forgetting look-ahead caching). For random access matrix is faster. Actually -- it depends. Removing the tail and inserting at tail is amortised constant time for arrays if done using the double-on-full trick. In that case, array can be the faster datastructure too. Joerg ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question
On Friday 23 April 2010 17:40:12 Joerg Sonnenberger wrote: On Fri, Apr 23, 2010 at 06:18:46PM +0300, Eitan Adler wrote: - use a matrix is faster than use a linked list? For what? For insertion and deletion no - linked list is faster. For sequential access they are the same speed (forgetting look-ahead caching). For random access matrix is faster. Actually -- it depends. Removing the tail and inserting at tail is amortised constant time for arrays if done using the double-on-full trick. In that case, array can be the faster datastructure too. Random deletes can be made O(1) if you don't care about the order of the elements in an array. - Pieter ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
c question
hello all
i want to know your oppinions about this:
- use a matrix is faster than use a linked list?
example:
char *szColumnName[10];
unsigned short iColumnAge[10];
struct _llList {
struct _llList *prev, *next;
char szName[64];
unsigned short iAge;
};
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Re: c question
2010/4/9 Leinier Cruz Salfran salfrancl.lis...@gmail.com
- use a matrix is faster than use a linked list?
example:
char *szColumnName[10];
unsigned short iColumnAge[10];
struct _llList {
struct _llList *prev, *next;
char szName[64];
unsigned short iAge;
};
Leinier ,
This depends on what kind of operations are performed. For sequential
traversing, both are very appropriate. However, you can not perform a binary
search on a list. You also can not combine two arrays into a single one with
constant complexity.
Lists also have greater memory overhead for small structures.
My advice: always use arrays.
Use lists if:
1) Copying items when the dynamic arrays grows is inappropriate.
2) List-specific operations like O(1) splicing or O(1) insertions and
deletions are required.
Alexander Churanov
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Re: c question
On Fri, Apr 9, 2010 at 10:52 AM, Alexander Churanov
alexanderchura...@gmail.com wrote:
2010/4/9 Leinier Cruz Salfran salfrancl.lis...@gmail.com
- use a matrix is faster than use a linked list?
example:
char *szColumnName[10];
unsigned short iColumnAge[10];
struct _llList {
struct _llList *prev, *next;
char szName[64];
unsigned short iAge;
};
Leinier ,
This depends on what kind of operations are performed. For sequential
traversing, both are very appropriate. However, you can not perform a binary
search on a list. You also can not combine two arrays into a single one with
constant complexity.
Lists also have greater memory overhead for small structures.
My advice: always use arrays.
Use lists if:
1) Copying items when the dynamic arrays grows is inappropriate.
2) List-specific operations like O(1) splicing or O(1) insertions and
deletions are required.
Alexander Churanov
hello alexander
i supposed that a matrix is much faster .. i coded my program to use
matrix in that portion but i sent the question to see what others
think about this
thanks
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Re: c question
On Fri, 9 Apr 2010, Leinier Cruz Salfran wrote:
hello all
i want to know your oppinions about this:
- use a matrix is faster than use a linked list?
yes.
example:
char *szColumnName[10];
unsigned short iColumnAge[10];
struct _llList {
struct _llList *prev, *next;
char szName[64];
unsigned short iAge;
};
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(415) 902 5513 cellular
http://kayve.net
Webmaster http://ChessYoga.org
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Re: c question: *printf'ing arrays
thx for all the great help guys.
cheers,
alex
Carlos A. M. dos Santos schrieb am 2009-07-02:
2009/7/2 Dag-Erling Smørgrav d...@des.no:
Alexander Best alexbes...@math.uni-muenster.de writes:
for (i=0; i sizeof(hdr-nintendo_logo); i++)
fprintf(stderr, %x, hdr-nintendo_logo[i]);
What will this print if nintendo_logo is { 0x01, 0x02, 0x03, 0x04
}?
Good catch. It will print 0x1234 but it should print 0x01020304.
My example has the same error. The conversion specification should be
%02x, not just %x.
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Re: c question: *printf'ing arrays
On Tue, 30 Jun 2009 20:21:03 +0200 (CEST), Alexander Best alexbes...@math.uni-muenster.de wrote: thanks. now the output gets redirected using . i'm quite new to programming under unix. sorry for the inconvenience. so i guess there is no really easy way to output an inhomogeneous struct to stdout without using a loop to output each array contained in the struct. No not really. You have to do the sizeof() dance. ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question: *printf'ing arrays
On Wed, 01 Jul 2009 00:06:05 +0200 (CEST), Alexander Best
alexbes...@math.uni-muenster.de wrote:
thanks for all the help. i decided to take the pill and coded all the
fprintfs by hand. here's the result. usually i'd stick to a higher
level languag, but i need C's inline assembly support:
struct Header
{
u_int8_t rom_entry[4];
u_int8_t nintendo_logo[156];
...
fprintf(stderr, \nNintendo Logo: 0x);
for (i=0; i sizeof(hdr-nintendo_logo); i++)
fprintf(stderr, %x, hdr-nintendo_logo[i]);
Note that %x will only print *one* digit for values smaller than 16,
i.e. printf(%x, 10) = a, so it may be useful to use %02x instead.
fprintf(stderr, \nFixed Value: 0x);
fprintf(stderr, %x, hdr-fixed_val);
For multi-byte fields, it makes sense to print 0x first and then
iterate. For single-byte values, it's probably a tiny bit faster to go
only _once_ through for *printf() family formatter, i.e.:
- fprintf(stderr, \nFixed Value: 0x);
- fprintf(stderr, %x, hdr-fixed_val);
+ fprintf(stderr, \nFixed Value: 0x%x, hdr-fixed_val);
Another nit that I noticed is that your last line doesn't end with \n:
fprintf(stderr, \nJoybus Entry Point: 0x);
for (i=0; i sizeof(hdr-joybus_entry); i++) fprintf(stderr, %x,
hdr-joybus_entry[i]);
Some terminal setups will *not* output the last line if it does not
finish properly with a \n, so it may be worth editing the code to
avoid the \nXXX format idiom, and go for a format style that puts
\n at the _end_ of output lines:
fprintf(stderr, Nintendo Logo: 0x);
for (i = 0; i sizeof(hdr-nintendo_logo); i++)
fprintf(stderr, %02x, hdr-nintendo_logo[i]);
fprintf(stderr, \n);
fprintf(stderr, Fixed Value: 0x%02x\n, hdr-fixed_val);
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Re: c question: *printf'ing arrays
2009/7/4 Giorgos Keramidas keram...@ceid.upatras.gr: [snip] s/0x%/%#.2hh/g -- Igor ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question: *printf'ing arrays
Alexander Best alexbes...@math.uni-muenster.de writes:
for (i=0; i sizeof(hdr-nintendo_logo); i++)
fprintf(stderr, %x, hdr-nintendo_logo[i]);
What will this print if nintendo_logo is { 0x01, 0x02, 0x03, 0x04 }?
DES
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Re: c question: *printf'ing arrays
2009/7/2 Dag-Erling Smørgrav d...@des.no:
Alexander Best alexbes...@math.uni-muenster.de writes:
for (i=0; i sizeof(hdr-nintendo_logo); i++)
fprintf(stderr, %x, hdr-nintendo_logo[i]);
What will this print if nintendo_logo is { 0x01, 0x02, 0x03, 0x04 }?
Good catch. It will print 0x1234 but it should print 0x01020304.
My example has the same error. The conversion specification should be
%02x, not just %x.
--
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omelettes, but because I like the sound of eggs being broken.
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Re: c question: *printf'ing arrays
On Tue, Jun 30, 2009 at 7:54 PM, Alfred Perlsteinalf...@freebsd.org wrote:
Hey Alex,
People frown on macros, but this could be a good one:
#define SPRINT(f, fmt) \
do {\
for (_i = 0; _i sizeof(f)/sizeof(f[0]); i++) \
printf(fmt, f[i]); \
}while(0)
:D
This should allow you to point to any _array_ and print each
element of it using format fmt.
Example:
SPRINT(Header-game_title, %c);
Yes, it works, but using a loop to print a character array one char at
a time is terribly inefficient.
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omelettes, but because I like the sound of eggs being broken.
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Re: c question: *printf'ing arrays
On Tue, Jun 30, 2009 at 7:06 PM, Alexander
Bestalexbes...@math.uni-muenster.de wrote:
thanks for all the help. i decided to take the pill and coded all the fprintfs
by hand. here's the result. usually i'd stick to a higher level languag, but i
need C's inline assembly support:
struct Header
{
u_int8_t rom_entry[4];
u_int8_t nintendo_logo[156];
u_char game_title[12];
u_char game_code[4];
u_char maker_code[2];
u_int8_t fixed_val;
u_int8_t unit_code;
u_int8_t device_type;
u_int8_t reserved_area1[7];
u_int8_t software_version;
u_int8_t complement_check;
u_int8_t reserved_area2;
u_int8_t ram_entry[4];
u_int8_t boot_mode;
u_int8_t slave_id;
u_int8_t unused_area[26];
u_int8_t joybus_entry[4];
};
struct Header * hdr = rom;
int i;
fprintf(stderr, ROM Entry: 0x);
for (i=0; i 4; i++) fprintf(stderr, %x, hdr-rom_entry[i]);
fprintf(stderr, \nNintendo Logo: 0x);
for (i=0; i sizeof(hdr-nintendo_logo); i++) fprintf(stderr, %x,
hdr-nintendo_logo[i]);
fprintf(stderr, \nGame Title: %s, hdr-game_title);
fprintf(stderr, \nGame Code: %s, hdr-game_code);
fprintf(stderr, \nMaker Code: %s, hdr-maker_code);
fprintf(stderr, \nFixed Value: 0x);
fprintf(stderr, %x, hdr-fixed_val);
fprintf(stderr, \nUnit Code: 0x);
fprintf(stderr, %x, hdr-unit_code);
fprintf(stderr, \nDevice Type: 0x);
fprintf(stderr, %x, hdr-device_type);
fprintf(stderr, \nReserved Area: 0x);
for (i=0; i sizeof(hdr-reserved_area1); i++) fprintf(stderr, %x,
hdr-reserved_area1[i]);
fprintf(stderr, \nSoftware Version: 0x);
fprintf(stderr, %x, hdr-software_version);
fprintf(stderr, \nComplement Check: 0x);
fprintf(stderr, %x, hdr-complement_check);
fprintf(stderr, \nReserved Area: 0x);
fprintf(stderr, %x, hdr-reserved_area2);
fprintf(stderr, \nRAM Entry Point: 0x);
for (i=0; i sizeof(hdr-ram_entry); i++) fprintf(stderr, %x,
hdr-ram_entry[i]);
fprintf(stderr, \nBoot Mode: 0x);
fprintf(stderr, %x, hdr-boot_mode);
fprintf(stderr, \nSlave ID: 0x);
fprintf(stderr, %x, hdr-slave_id);
fprintf(stderr, \nUnused Area: 0x);
for (i=0; i sizeof(hdr-unused_area); i++) fprintf(stderr, %x,
hdr-unused_area[i]);
fprintf(stderr, \nJoybus Entry Point: 0x);
for (i=0; i sizeof(hdr-joybus_entry); i++) fprintf(stderr, %x,
hdr-joybus_entry[i]);
The code below is a bit more efficient and easier to read. It is also
safer, since it limits the width of the %s conversions to the sizes of
the corresponding arrays.
fprintf(stderr, ROM Entry: 0x);
for (i=0; i 4; i++)
fprintf(stderr, %x, hdr-rom_entry[i]);
fprintf(stderr, \nNintendo Logo: 0x);
for (i=0; i sizeof(hdr-nintendo_logo); i++)
fprintf(stderr, %x, hdr-nintendo_logo[i]);
fprintf(stderr,
\nGame Title: %.*s
\nGame Code: %.*s
\nMaker Code: %.*s
\nFixed Value: 0x%x
\nUnit Code: 0x%x
\nDevice Type: 0x%x
\nReserved Area: 0x,
sizeof(hdr-game_title), hdr-game_title,
sizeof(hdr-game_code), hdr-game_code,
sizeof(hdr-maker_code), hdr-maker_code,
hdr-fixed_val,
hdr-unit_code,
hdr-device_type);
for (i=0; i sizeof(hdr-reserved_area1); i++)
fprintf(stderr, %x, hdr-reserved_area1[i]);
fprintf(stderr,
\nSoftware Version: 0x%x
\nComplement Check: 0x%x
\nReserved Area: 0x%x
\nRAM Entry Point: 0x,
hdr-software_version,
hdr-complement_check,
hdr-reserved_area2);
for (i=0; i sizeof(hdr-ram_entry); i++)
fprintf(stderr, %x, hdr-ram_entry[i]);
fprintf(stderr,
\nBoot Mode: 0x%x
\nSlave ID: 0x%x
\nUnused Area: 0x,
hdr-boot_mode,
hdr-slave_id);
for (i=0; i sizeof(hdr-unused_area); i++)
fprintf(stderr, %x, hdr-unused_area[i]);
fprintf(stderr, \nJoybus Entry Point: 0x);
for (i=0; i sizeof(hdr-joybus_entry); i++)
fprintf(stderr, %x, hdr-joybus_entry[i]);
fprintf(stderr, \n);
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make an omelette without breaking eggs. Not because I like the
omelettes, but because I like the sound of eggs being broken.
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c question: *printf'ing arrays
hi there,
i need to output the header of a file to stdout. the header looks like this:
struct Header
{
u_int8_t rom_entry[4];
u_int8_t nintendo_logo[156];
u_char game_title[12];
u_char game_code[4];
u_char maker_code[2];
u_int8_t fixed_val;
u_int8_t unit_code;
u_int8_t device_type;
u_int8_t reserved_area1[7];
u_int8_t software_version;
u_int8_t complement_check;
u_int8_t reserved_area2;
u_int8_t ram_entry[4];
u_int8_t boot_mode;
u_int8_t slave_id;
u_int8_t unused_area[26];
u_int8_t joybus_entry[4];
};
if there a way to use printf or some other variant of *printf without using
sizeof()-loops for all the arrays?
cheers.
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Re: c question: *printf'ing arrays
On Tue, 2009-06-30 at 18:12 +0200, Alexander Best wrote:
hi there,
i need to output the header of a file to stdout. the header looks like this:
struct Header
{
u_int8_t rom_entry[4];
u_int8_t nintendo_logo[156];
u_char game_title[12];
u_char game_code[4];
u_char maker_code[2];
u_int8_t fixed_val;
u_int8_t unit_code;
u_int8_t device_type;
u_int8_t reserved_area1[7];
u_int8_t software_version;
u_int8_t complement_check;
u_int8_t reserved_area2;
u_int8_t ram_entry[4];
u_int8_t boot_mode;
u_int8_t slave_id;
u_int8_t unused_area[26];
u_int8_t joybus_entry[4];
};
if there a way to use printf or some other variant of *printf without using
sizeof()-loops for all the arrays?
cheers.
None of your arrays are dynamically sized, so surely
write(fd, hdr, sizeof(Header));
would do the trick?
Cheers
Tom
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Re: c question: *printf'ing arrays
thanks. but that simply dumps the contents of the struct to stdout. but since
most of the struct's contents aren't ascii the output isn't really of much
use.
cheers.
Tom Evans schrieb am 2009-06-30:
On Tue, 2009-06-30 at 18:12 +0200, Alexander Best wrote:
hi there,
i need to output the header of a file to stdout. the header looks
like this:
struct Header
{
u_int8_t rom_entry[4];
u_int8_t nintendo_logo[156];
u_char game_title[12];
u_char game_code[4];
u_char maker_code[2];
u_int8_t fixed_val;
u_int8_t unit_code;
u_int8_t device_type;
u_int8_t reserved_area1[7];
u_int8_t software_version;
u_int8_t complement_check;
u_int8_t reserved_area2;
u_int8_t ram_entry[4];
u_int8_t boot_mode;
u_int8_t slave_id;
u_int8_t unused_area[26];
u_int8_t joybus_entry[4];
};
if there a way to use printf or some other variant of *printf
without using
sizeof()-loops for all the arrays?
cheers.
None of your arrays are dynamically sized, so surely
write(fd, hdr, sizeof(Header));
would do the trick?
Cheers
Tom
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Re: c question: *printf'ing arrays
that works, but i really want to have a pretty output to stdout. i guess i have to stick with printf and use `for (i=0; i sizeof(XXX); i++)` for each array in the struct. just thought i could avoid it. btw. `./my-program | hexdump` works, but if i do `./my-program output` output is being created, but is empty. is this normal? cheers. Igor Mozolevsky schrieb am 2009-06-30: 2009/6/30 Alexander Best alexbes...@math.uni-muenster.de: thanks. but that simply dumps the contents of the struct to stdout. but since most of the struct's contents aren't ascii the output isn't really of much use. How about ./your-program | hexdump ? -- Igor ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question: *printf'ing arrays
2009/6/30 Alexander Best alexbes...@math.uni-muenster.de: that works, but i really want to have a pretty output to stdout. i guess i have to stick with printf and use `for (i=0; i sizeof(XXX); i++)` for each array in the struct. just thought i could avoid it. btw. `./my-program | hexdump` works, but if i do `./my-program output` output is being created, but is empty. is this normal? Depends if you output to stdout or stderr --- `' redirects stdout. Cheers, -- Igor ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question: *printf'ing arrays
should be stdout. struct Header *hdr = rom; int new_fd = open(/dev/stdout, O_RDWR); printf(SIZE: %d\n,sizeof(*hdr)); write(new_fd, hdr, sizeof(*hdr)); close(new_fd); Igor Mozolevsky schrieb am 2009-06-30: 2009/6/30 Alexander Best alexbes...@math.uni-muenster.de: that works, but i really want to have a pretty output to stdout. i guess i have to stick with printf and use `for (i=0; i sizeof(XXX); i++)` for each array in the struct. just thought i could avoid it. btw. `./my-program | hexdump` works, but if i do `./my-program output` output is being created, but is empty. is this normal? Depends if you output to stdout or stderr --- `' redirects stdout. Cheers, -- Igor ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question: *printf'ing arrays
On Tue, Jun 30, 2009 at 08:03:21PM +0200, Alexander Best wrote: should be stdout. struct Header *hdr = rom; int new_fd = open(/dev/stdout, O_RDWR); printf(SIZE: %d\n,sizeof(*hdr)); write(new_fd, hdr, sizeof(*hdr)); close(new_fd); Why are you reopening stdout? It should already be open, so use fileno(stdout) or just plain STDOUT_FILENO instead of new_fd. -- Rick C. Petty ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question: *printf'ing arrays
2009/6/30 Alexander Best alexbes...@math.uni-muenster.de: thanks. but that simply dumps the contents of the struct to stdout. but since most of the struct's contents aren't ascii the output isn't really of much use. How about ./your-program | hexdump ? -- Igor ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question: *printf'ing arrays
2009/6/30 Alexander Best alexbes...@math.uni-muenster.de:
should be stdout.
struct Header *hdr = rom;
int new_fd = open(/dev/stdout, O_RDWR);
printf(SIZE: %d\n,sizeof(*hdr));
write(new_fd, hdr, sizeof(*hdr));
close(new_fd);
You should really be checking what open returns, opening /dev/stdout
for reading is a bit weird not sure if that would work, and most
likely it's already open... Just use fileno(...):-
#include unistd.h
#include stdio.h
int main(void) {
write(fileno(stdout), Hello world!\n, 13);
return 0;
}
Cheers,
--
Igor
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Re: c question: *printf'ing arrays
thanks. now the output gets redirected using . i'm quite new to programming under unix. sorry for the inconvenience. so i guess there is no really easy way to output an inhomogeneous struct to stdout without using a loop to output each array contained in the struct. cheers. Rick C. Petty schrieb am 2009-06-30: On Tue, Jun 30, 2009 at 08:03:21PM +0200, Alexander Best wrote: should be stdout. struct Header *hdr = rom; int new_fd = open(/dev/stdout, O_RDWR); printf(SIZE: %d\n,sizeof(*hdr)); write(new_fd, hdr, sizeof(*hdr)); close(new_fd); Why are you reopening stdout? It should already be open, so use fileno(stdout) or just plain STDOUT_FILENO instead of new_fd. -- Rick C. Petty ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question: *printf'ing arrays
On Tue, Jun 30, 2009 at 08:21:03PM +0200, Alexander Best wrote: thanks. now the output gets redirected using . i'm quite new to programming under unix. sorry for the inconvenience. No problem; we all had to learn sometime. But what I suggested should work for every platform that adheres to POSIX. If you were using fprintf/fwrite, then it would work on anything that's standard C. As for redirection, windows command line allows the same type of redirection. so i guess there is no really easy way to output an inhomogeneous struct to stdout without using a loop to output each array contained in the struct. That's not something C would ever provide easily. You may want to use a different high-level language. However, I often use macros for printing pieces of structures, for example I used this to print out sizes of kernel structures: #define SIZE(astruct, member) \ printf(%d\t\t.%s\n, sizeof(astruct.member), #member) #include sys/ktrace.h ... struct ktr_header header; struct ktr_genio genio; printf(%d\tktr_header:\n, sizeof(header)); SIZE(header, ktr_len); SIZE(header, ktr_type); SIZE(header, ktr_pid); SIZE(header, ktr_comm); SIZE(header, ktr_time); SIZE(header, ktr_time.tv_sec); SIZE(header, ktr_time.tv_sec); SIZE(header, ktr_tid); printf(\n%d\tktr_genio:\n, sizeof(genio)); SIZE(genio, ktr_fd); SIZE(genio, ktr_rw); In your case, you could make a macro for each type. Without an example of how you want the output to look, it's hard for us to show you code that will produce such output. -- Rick C. Petty ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: c question: *printf'ing arrays
Hey Alex,
People frown on macros, but this could be a good one:
#define SPRINT(f, fmt) \
do {\
for (_i = 0; _i sizeof(f)/sizeof(f[0]); i++) \
printf(fmt, f[i]); \
}while(0)
:D
This should allow you to point to any _array_ and print each
element of it using format fmt.
Example:
SPRINT(Header-game_title, %c);
-Alfred
* Alexander Best alexbes...@math.uni-muenster.de [090630 15:06] wrote:
thanks for all the help. i decided to take the pill and coded all the fprintfs
by hand. here's the result. usually i'd stick to a higher level languag, but i
need C's inline assembly support:
struct Header
{
u_int8_t rom_entry[4];
u_int8_t nintendo_logo[156];
u_char game_title[12];
u_char game_code[4];
u_char maker_code[2];
u_int8_t fixed_val;
u_int8_t unit_code;
u_int8_t device_type;
u_int8_t reserved_area1[7];
u_int8_t software_version;
u_int8_t complement_check;
u_int8_t reserved_area2;
u_int8_t ram_entry[4];
u_int8_t boot_mode;
u_int8_t slave_id;
u_int8_t unused_area[26];
u_int8_t joybus_entry[4];
};
struct Header * hdr = rom;
int i;
fprintf(stderr, ROM Entry: 0x);
for (i=0; i 4; i++) fprintf(stderr, %x, hdr-rom_entry[i]);
fprintf(stderr, \nNintendo Logo: 0x);
for (i=0; i sizeof(hdr-nintendo_logo); i++) fprintf(stderr, %x,
hdr-nintendo_logo[i]);
fprintf(stderr, \nGame Title: %s, hdr-game_title);
fprintf(stderr, \nGame Code: %s, hdr-game_code);
fprintf(stderr, \nMaker Code: %s, hdr-maker_code);
fprintf(stderr, \nFixed Value: 0x);
fprintf(stderr, %x, hdr-fixed_val);
fprintf(stderr, \nUnit Code: 0x);
fprintf(stderr, %x, hdr-unit_code);
fprintf(stderr, \nDevice Type: 0x);
fprintf(stderr, %x, hdr-device_type);
fprintf(stderr, \nReserved Area: 0x);
for (i=0; i sizeof(hdr-reserved_area1); i++) fprintf(stderr, %x,
hdr-reserved_area1[i]);
fprintf(stderr, \nSoftware Version: 0x);
fprintf(stderr, %x, hdr-software_version);
fprintf(stderr, \nComplement Check: 0x);
fprintf(stderr, %x, hdr-complement_check);
fprintf(stderr, \nReserved Area: 0x);
fprintf(stderr, %x, hdr-reserved_area2);
fprintf(stderr, \nRAM Entry Point: 0x);
for (i=0; i sizeof(hdr-ram_entry); i++) fprintf(stderr, %x,
hdr-ram_entry[i]);
fprintf(stderr, \nBoot Mode: 0x);
fprintf(stderr, %x, hdr-boot_mode);
fprintf(stderr, \nSlave ID: 0x);
fprintf(stderr, %x, hdr-slave_id);
fprintf(stderr, \nUnused Area: 0x);
for (i=0; i sizeof(hdr-unused_area); i++) fprintf(stderr, %x,
hdr-unused_area[i]);
fprintf(stderr, \nJoybus Entry Point: 0x);
for (i=0; i sizeof(hdr-joybus_entry); i++) fprintf(stderr, %x,
hdr-joybus_entry[i]);
cheers.
Rick C. Petty schrieb am 2009-06-30:
On Tue, Jun 30, 2009 at 08:21:03PM +0200, Alexander Best wrote:
thanks. now the output gets redirected using . i'm quite new to
programming
under unix. sorry for the inconvenience.
No problem; we all had to learn sometime. But what I suggested
should
work for every platform that adheres to POSIX. If you were using
fprintf/fwrite, then it would work on anything that's standard C. As
for
redirection, windows command line allows the same type of
redirection.
so i guess there is no really easy way to output an inhomogeneous
struct to
stdout without using a loop to output each array contained in the
struct.
That's not something C would ever provide easily. You may want to
use a
different high-level language. However, I often use macros for
printing
pieces of structures, for example I used this to print out sizes of
kernel
structures:
#define SIZE(astruct, member) \
printf(%d\t\t.%s\n, sizeof(astruct.member), #member)
#include sys/ktrace.h
...
struct ktr_header header;
struct ktr_genio genio;
printf(%d\tktr_header:\n, sizeof(header));
SIZE(header, ktr_len);
SIZE(header, ktr_type);
SIZE(header, ktr_pid);
SIZE(header, ktr_comm);
SIZE(header, ktr_time);
SIZE(header, ktr_time.tv_sec);
SIZE(header, ktr_time.tv_sec);
SIZE(header, ktr_tid);
printf(\n%d\tktr_genio:\n, sizeof(genio));
SIZE(genio, ktr_fd);
SIZE(genio, ktr_rw);
In your case, you could make a macro for each type. Without an
example of
how you want the output to look, it's hard for us to show you code
that
will produce such output.
-- Rick C. Petty
___
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Re: c question: *printf'ing arrays
wow. thanks. that's looking really nice. i'll change my sources tomorrow after
a good dose of sleep. ;)
alex
Alfred Perlstein schrieb am 2009-07-01:
Hey Alex,
People frown on macros, but this could be a good one:
#define SPRINT(f, fmt) \
do {\
for (_i = 0; _i sizeof(f)/sizeof(f[0]); i++) \
printf(fmt, f[i]); \
}while(0)
:D
This should allow you to point to any _array_ and print each
element of it using format fmt.
Example:
SPRINT(Header-game_title, %c);
-Alfred
* Alexander Best alexbes...@math.uni-muenster.de [090630 15:06]
wrote:
thanks for all the help. i decided to take the pill and coded all
the fprintfs
by hand. here's the result. usually i'd stick to a higher level
languag, but i
need C's inline assembly support:
struct Header
{
u_int8_t rom_entry[4];
u_int8_t nintendo_logo[156];
u_char game_title[12];
u_char game_code[4];
u_char maker_code[2];
u_int8_t fixed_val;
u_int8_t unit_code;
u_int8_t device_type;
u_int8_t reserved_area1[7];
u_int8_t software_version;
u_int8_t complement_check;
u_int8_t reserved_area2;
u_int8_t ram_entry[4];
u_int8_t boot_mode;
u_int8_t slave_id;
u_int8_t unused_area[26];
u_int8_t joybus_entry[4];
};
struct Header * hdr = rom;
int i;
fprintf(stderr, ROM Entry: 0x);
for (i=0; i 4; i++) fprintf(stderr, %x, hdr-rom_entry[i]);
fprintf(stderr, \nNintendo Logo: 0x);
for (i=0; i sizeof(hdr-nintendo_logo); i++) fprintf(stderr,
%x,
hdr-nintendo_logo[i]);
fprintf(stderr, \nGame Title: %s, hdr-game_title);
fprintf(stderr, \nGame Code: %s, hdr-game_code);
fprintf(stderr, \nMaker Code: %s, hdr-maker_code);
fprintf(stderr, \nFixed Value: 0x);
fprintf(stderr, %x, hdr-fixed_val);
fprintf(stderr, \nUnit Code: 0x);
fprintf(stderr, %x, hdr-unit_code);
fprintf(stderr, \nDevice Type: 0x);
fprintf(stderr, %x, hdr-device_type);
fprintf(stderr, \nReserved Area: 0x);
for (i=0; i sizeof(hdr-reserved_area1); i++) fprintf(stderr,
%x,
hdr-reserved_area1[i]);
fprintf(stderr, \nSoftware Version: 0x);
fprintf(stderr, %x, hdr-software_version);
fprintf(stderr, \nComplement Check: 0x);
fprintf(stderr, %x, hdr-complement_check);
fprintf(stderr, \nReserved Area: 0x);
fprintf(stderr, %x, hdr-reserved_area2);
fprintf(stderr, \nRAM Entry Point: 0x);
for (i=0; i sizeof(hdr-ram_entry); i++) fprintf(stderr,
%x,
hdr-ram_entry[i]);
fprintf(stderr, \nBoot Mode: 0x);
fprintf(stderr, %x, hdr-boot_mode);
fprintf(stderr, \nSlave ID: 0x);
fprintf(stderr, %x, hdr-slave_id);
fprintf(stderr, \nUnused Area: 0x);
for (i=0; i sizeof(hdr-unused_area); i++) fprintf(stderr,
%x,
hdr-unused_area[i]);
fprintf(stderr, \nJoybus Entry Point: 0x);
for (i=0; i sizeof(hdr-joybus_entry); i++) fprintf(stderr,
%x,
hdr-joybus_entry[i]);
cheers.
Rick C. Petty schrieb am 2009-06-30:
On Tue, Jun 30, 2009 at 08:21:03PM +0200, Alexander Best wrote:
thanks. now the output gets redirected using . i'm quite new
to
programming
under unix. sorry for the inconvenience.
No problem; we all had to learn sometime. But what I suggested
should
work for every platform that adheres to POSIX. If you were using
fprintf/fwrite, then it would work on anything that's standard C.
As
for
redirection, windows command line allows the same type of
redirection.
so i guess there is no really easy way to output an
inhomogeneous
struct to
stdout without using a loop to output each array contained in
the
struct.
That's not something C would ever provide easily. You may want
to
use a
different high-level language. However, I often use macros for
printing
pieces of structures, for example I used this to print out sizes
of
kernel
structures:
#define SIZE(astruct, member) \
printf(%d\t\t.%s\n, sizeof(astruct.member), #member)
#include sys/ktrace.h
...
struct ktr_header header;
struct ktr_genio genio;
printf(%d\tktr_header:\n, sizeof(header));
SIZE(header, ktr_len);
SIZE(header, ktr_type);
SIZE(header, ktr_pid);
SIZE(header, ktr_comm);
SIZE(header, ktr_time);
SIZE(header, ktr_time.tv_sec);
SIZE(header, ktr_time.tv_sec);
SIZE(header, ktr_tid);
printf(\n%d\tktr_genio:\n, sizeof(genio));
SIZE(genio, ktr_fd);
SIZE(genio, ktr_rw);
In your case, you could make a macro for each type. Without an
example of
how you want the output to look, it's hard for us to
Re: Port-related C++ question
Jos Backus [EMAIL PROTECTED] writes: On Sat, Apr 28, 2001 at 09:32:51PM -0700, Dima Dorfman wrote: Jos Backus [EMAIL PROTECTED] writes: void stdin(const Config config); -=== line 99 `stdin' is a global variable which, surprisingly enough, refers to the standard input stream. Don't name a function after it and your problem should go away. Yeah, I am just puzzled as to how this can build at all on other platforms (Linux?), unless they don't define this variable. I don't know how other systems do it, but I can imagine that they could define `stdin' as a real global variable--as compared to a #define in FreeBSD. Then the above just spams over the symbol. I don't know the details of C's scoping rules to know if that would work as they want it, but I guess it's possible. Thanks, -- Jos Backus _/ _/_/_/Modularity is not a hack. _/ _/ _/-- D. J. Bernstein _/ _/_/_/ _/ _/ _/_/ [EMAIL PROTECTED] _/_/ _/_/_/use Std::Disclaimer; To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Port-related C++ question
In message [EMAIL PROTECTED], Jos Backus writes: Yeah, I am just puzzled as to how this can build at all on other platforms (Linux?), unless they don't define this variable. Many of them probably have it as an external object, not a #define. I'm still not sure the code makes any sense. -s To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Port-related C++ question
In message [EMAIL PROTECTED] Peter Seebach writes: : In message [EMAIL PROTECTED], Jos Backus writes: : Yeah, I am just puzzled as to how this can build at all on other platforms : (Linux?), unless they don't define this variable. : : Many of them probably have it as an external object, not a #define. I'm : still not sure the code makes any sense. The standards allow for it to be a #define (just like they allow errno to be a #define), so code that uses like the code that was posted earlier is not strictly conforming. Warner To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Port-related C++ question
[Apologies if this is the wrong list for this type of question.]
I am trying to create a port for a commandline-accessible database tool, but I
am running into the following problem (on RELENG_4 as of today):
=== Building for dbtool-1.3
c++ -DPACKAGE=\dbtool\ -DVERSION=\1.3\ -DSTDC_HEADERS=1 -DHAVE_UNISTD_H=1
-DHAVE_STDIO_H=1 -DHAVE_STDLIB_H=1 -DHAVE_LIBPCRE=1 -DHAVE_GETOPT=1 -DHAVE_FDOPEN=1
-DHAVE_FGETC=1 -DHAVE_GETENV=1 -DHAVE_BERKELEY=1 -I. -I.-I/usr/local/include/db3
-Wall -Wstrict-prototypes -O2 -c cmd.cc
In file included from cmd.cc:22:
dbtool.h:99: declaration of `__sF' as array of references
gmake: *** [cmd.o] Error 1
*** Error code 2
/*
* The Engine class will do all gdbm related stuff, i.e.
* insert, search, create, remove and so on.
* methods defined in engine.cc
*/
class Engine {
private:
void init(const Config config); /* init() will be called from every member once */
#ifdef HAVE_BERKELEY
Db *db;
#else
GDBM_FILE db;
#endif
string pkg;
public:
Engine() {;;};
void insert(const Config config);
void update(const Config config);
void remove(const Config config);
void select(const Config config);
void stdin(const Config config); -=== line 99
void dump(const Config config);
void regexp(const Config config);
};
Anyone have any ideas on how to fix this?
Thanks,
--
Jos Backus _/ _/_/_/Modularity is not a hack.
_/ _/ _/-- D. J. Bernstein
_/ _/_/_/
_/ _/ _/_/
[EMAIL PROTECTED] _/_/ _/_/_/use Std::Disclaimer;
To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-hackers in the body of the message
Re: Port-related C++ question
Jos Backus [EMAIL PROTECTED] writes: void stdin(const Config config); -=== line 99 `stdin' is a global variable which, surprisingly enough, refers to the standard input stream. Don't name a function after it and your problem should go away. To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Port-related C++ question
In message [EMAIL PROTECTED] Jos Backus writes: : dbtool.h:99: declaration of `__sF' as array of references : void stdin(const Config config); -=== line 99 stdin is #defined to be __sF[0]. Warner To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Port-related C++ question
On Sat, Apr 28, 2001 at 09:32:51PM -0700, Dima Dorfman wrote: Jos Backus [EMAIL PROTECTED] writes: void stdin(const Config config); -=== line 99 `stdin' is a global variable which, surprisingly enough, refers to the standard input stream. Don't name a function after it and your problem should go away. Yeah, I am just puzzled as to how this can build at all on other platforms (Linux?), unless they don't define this variable. Thanks, -- Jos Backus _/ _/_/_/Modularity is not a hack. _/ _/ _/-- D. J. Bernstein _/ _/_/_/ _/ _/ _/_/ [EMAIL PROTECTED] _/_/ _/_/_/use Std::Disclaimer; To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: X11/C++ question
In message [EMAIL PROTECTED] Chuck Robey writes: : Does anyone (anyone, that is, who's coded X11 applications) know how you : handle X11 callbacks to C++ object methods? OI_add_event(3OI) :-) Warner To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
On Wed, 3 Nov 1999, Warner Losh wrote: In message [EMAIL PROTECTED] Chuck Robey writes: : Does anyone (anyone, that is, who's coded X11 applications) know how you : handle X11 callbacks to C++ object methods? OI_add_event(3OI) :-) Uhhh? I've long since got the answer I wanted, but this seems a complete mystery, so I'll bite, what's a OI_add_event? From some package? Can't find a man page on it. Warner Chuck Robey| Interests include C programming, Electronics, 213 Lakeside Dr. Apt. T-1 | communications, and signal processing. Greenbelt, MD 20770| I run picnic.mat.net: FreeBSD-current(i386) and (301) 220-2114 | jaunt.mat.net : FreeBSD-current(Alpha) To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
In message [EMAIL PROTECTED] Chuck Robey writes: : Uhhh? I've long since got the answer I wanted, but this seems a complete : mystery, so I'll bite, what's a OI_add_event? From some package? Can't : find a man page on it. OI was a native C++ toolkit that had a nice interface and was ported to Linux and FreeBSD back in 1993 or so by yours truly. It was available from ParcPlace. Sadly, it never went anywhere and all efforts of the engineers to make it open sourced (this was in 1996) failed. It was ment as a joke for the long timers on the list... Warner To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
In message [EMAIL PROTECTED] Chuck Robey writes: : Uhhh? I've long since got the answer I wanted, but this seems a complete : mystery, so I'll bite, what's a OI_add_event? From some package? Can't : find a man page on it. OI was a native C++ toolkit that had a nice interface and was ported to Linux and FreeBSD back in 1993 or so by yours truly. It was available from ParcPlace. Sadly, it never went anywhere and all efforts of the engineers to make it open sourced (this was in 1996) failed. It was ment as a joke for the long timers on the list... Warner To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message Let me add that as a stock holder of ParcPlace (now ObjectShare) and one of the people who tried out OI - I was disappointed it didn't go anywhere. It seemed nice... (I wonder where it is now?) ObjectShare is trading right now at 44-cents/share - an amazing 18.92% increase so far for the day (up 7 cents). Perhaps that outstanding stock price reflects the outcome of some of their decisions? [I believe my last purchase of ObjectShare was somewhere in the $10 range... sigh.] - Dave Rivers - To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
hi,
Does anyone (anyone, that is, who's coded X11 applications) know how you
handle X11 callbacks to C++ object methods?
Thanks,
TDR If you mean Xt (and possibly Motif) - the answer is "very carefully."
TDR The Xt callbacks are C based, so you typically can't directly call a
TDR C++ method.
TDR But, you can have an extern "C" block that declares the call back
TDR function (the extern "C" basically keeps any name mangling from going on)
TDR and then, in that function, invoke the method as appropriate.
TDR I believe you do something like:
TDR class myclass {
TDR void mymethod(void * arg1) {
TDR cout "Ha! I got to the class" '\n';
TDR };
TDR }
TDR extern "C" {
TDR void
TDR callback_function(arg1)
TDR void *arg1;
TDR {
TDR /* Call the method */
TDR myclass::mymethod(arg1);
TDR }
TDR }
Looks good except one point -- mymethod should be static, i.e.
static void mymethod (...) {
...
}
TDR Then, you register "callback_function" as the Xt/Motif callback.
TDR I've at least "heard" of doing that kind of thing before...
--
/* Alexey Zelkin[EMAIL PROTECTED]*/
/* Tavric National University [EMAIL PROTECTED] */
/* http://www.ccssu.crimea.ua/~phantom [EMAIL PROTECTED] */
To Unsubscribe: send mail to [EMAIL PROTECTED]
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Re: X11/C++ question
[EMAIL PROTECTED] (Chuck Robey) writes: Boy, I sure wish Java compiled and ran natively. I'd stop using C++ forever. gcc-2.95.1 + libgcj already works, at least for simple programs. On FreeBSD 3.x programs seem to work as long as you use statically linked libraries (shared libraries cause the garbage collector to dump core). There already seems to be some awt code in libgcj, I have no idea whether it's actually functional. And the speed isn't quite comparable to what you can achieve lower-level languages (pretty close to the equivalent C++ code with all methods virtual, heavy use of rtti and common-base-class-based containers), but probably good enough for a lot of things. To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
Chuck Robey wrote: On Tue, 26 Oct 1999 [EMAIL PROTECTED] wrote: Thomas David Rivers writes: If you mean Xt (and possibly Motif) - the answer is "very carefully." [...] You're approach would probably work, but there's an easier way. See topic 28 in the Xt FAQ. ftp://ftp.x.org/contrib/faqs/FAQ-Xt It's not name mangling causing problems, it's lack of "this" when the method is invoked as a callback from Xt. Yes! This is the method! I like it, or at least, it's as close (in C++ code) to something I do like. I assume they're using a static member function for the callback and storing the this pointer for the object somewhere handy? This is the canonical way to re-enter C++ code from C land, and can even be used for C++ interrupt handlers if you're very careful. -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC [EMAIL PROTECTED] http://softweyr.com/ To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
On Wed, 27 Oct 1999, Wes Peters wrote: Chuck Robey wrote: On Tue, 26 Oct 1999 [EMAIL PROTECTED] wrote: Thomas David Rivers writes: If you mean Xt (and possibly Motif) - the answer is "very carefully." [...] You're approach would probably work, but there's an easier way. See topic 28 in the Xt FAQ. ftp://ftp.x.org/contrib/faqs/FAQ-Xt It's not name mangling causing problems, it's lack of "this" when the method is invoked as a callback from Xt. Yes! This is the method! I like it, or at least, it's as close (in C++ code) to something I do like. I assume they're using a static member function for the callback and storing the this pointer for the object somewhere handy? This is the canonical way to re-enter C++ code from C land, and can even be used for C++ interrupt handlers if you're very careful. Yes, you store the address of the object you want the callback vectored to in the UserData Xt pointer, and when the callback comes into the static func, it just takes the offered object address and reflects the call back out to the right function in the right object. Neat, the user never sees any complication at all. Chuck Robey| Interests include C programming, Electronics, 213 Lakeside Dr. Apt. T-1 | communications, and signal processing. Greenbelt, MD 20770| I run picnic.mat.net: FreeBSD-current(i386) and (301) 220-2114 | jaunt.mat.net : FreeBSD-current(Alpha) To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
X11/C++ question
Does anyone (anyone, that is, who's coded X11 applications) know how you handle X11 callbacks to C++ object methods? Thanks, Chuck Robey| Interests include C programming, Electronics, 213 Lakeside Dr. Apt. T-1 | communications, and signal processing. Greenbelt, MD 20770| I run picnic.mat.net: FreeBSD-current(i386) and (301) 220-2114 | jaunt.mat.net : FreeBSD-current(Alpha) To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
Does anyone (anyone, that is, who's coded X11 applications) know how you
handle X11 callbacks to C++ object methods?
Thanks,
If you mean Xt (and possibly Motif) - the answer is "very carefully."
The Xt callbacks are C based, so you typically can't directly call a
C++ method.
But, you can have an extern "C" block that declares the call back
function (the extern "C" basically keeps any name mangling from going on)
and then, in that function, invoke the method as appropriate.
I believe you do something like:
class myclass {
void mymethod(void * arg1) {
cout "Ha! I got to the class" '\n';
};
}
extern "C" {
void
callback_function(arg1)
void *arg1;
{
/* Call the method */
myclass::mymethod(arg1);
}
}
Then, you register "callback_function" as the Xt/Motif callback.
I've at least "heard" of doing that kind of thing before...
- Dave Rivers -
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Re: X11/C++ question
On 27-Oct-99 Thomas David Rivers wrote: If you mean Xt (and possibly Motif) - the answer is "very carefully." Or you could just use a toolkit written for C++ or with C++ shims already.. ie Qt or GTK.. --- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
On 27-Oct-99 Thomas David Rivers wrote: And, wasn't there a freely available C++ shim for motif floating around at one time? I don't know.. My X experience begins and ends with Tk :) (Don't like Motif either ;) --- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
On Tue, Oct 26, 1999, Thomas David Rivers wrote:
extern "C" {
void
callback_function(arg1)
void *arg1;
{
/* Call the method */
myclass::mymethod(arg1);
As far as I've seen, you can't directly call a class method
without an object.
--
|Chris Costello [EMAIL PROTECTED]
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Re: X11/C++ question
Thomas David Rivers writes: If you mean Xt (and possibly Motif) - the answer is "very carefully." [...] You're approach would probably work, but there's an easier way. See topic 28 in the Xt FAQ. ftp://ftp.x.org/contrib/faqs/FAQ-Xt It's not name mangling causing problems, it's lack of "this" when the method is invoked as a callback from Xt. -Ted To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
On Tue, 26 Oct 1999, Thomas David Rivers wrote: Does anyone (anyone, that is, who's coded X11 applications) know how you handle X11 callbacks to C++ object methods? Thanks, If you mean Xt (and possibly Motif) - the answer is "very carefully." The Xt callbacks are C based, so you typically can't directly call a C++ method. But, you can have an extern "C" block that declares the call back function (the extern "C" basically keeps any name mangling from going on) and then, in that function, invoke the method as appropriate. I believe you do something like: [example deleted] Then you just stick a C wrapper function around every C++ callback you want to register, is that it? Seems a bit inelegant, but I suppose, if the ultimate test of elegance is that "it's the only one that works", then it's perhaps elegant *enough*. Chuck Robey| Interests include C programming, Electronics, 213 Lakeside Dr. Apt. T-1 | communications, and signal processing. Greenbelt, MD 20770| I run picnic.mat.net: FreeBSD-current(i386) and (301) 220-2114 | jaunt.mat.net : FreeBSD-current(Alpha) To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
On Wed, 27 Oct 1999, Daniel O'Connor wrote: On 27-Oct-99 Thomas David Rivers wrote: If you mean Xt (and possibly Motif) - the answer is "very carefully." Or you could just use a toolkit written for C++ or with C++ shims already.. ie Qt or GTK.. If I wanted to just get X11 done, I would just call some toolkit. I didn't want to be told to go get something else that does it, I wanted to know the right way to do it myself. Thomas's post, at least, was really helpful. I wonder if that's really the way to go, but he surely did give me *one* method, and explained it easily enough so that I can *do* it. Boy, I sure wish Java compiled and ran natively. I'd stop using C++ forever. Chuck Robey| Interests include C programming, Electronics, 213 Lakeside Dr. Apt. T-1 | communications, and signal processing. Greenbelt, MD 20770| I run picnic.mat.net: FreeBSD-current(i386) and (301) 220-2114 | jaunt.mat.net : FreeBSD-current(Alpha) To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
Then you just stick a C wrapper function around every C++ callback you want to register, is that it? Seems a bit inelegant, but I suppose, if the ultimate test of elegance is that "it's the only one that works", then it's perhaps elegant *enough*. I believe someone posted a better solution... from the Xt FAQ. - Dave R. - To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
On Tue, 26 Oct 1999 [EMAIL PROTECTED] wrote: Thomas David Rivers writes: If you mean Xt (and possibly Motif) - the answer is "very carefully." [...] You're approach would probably work, but there's an easier way. See topic 28 in the Xt FAQ. ftp://ftp.x.org/contrib/faqs/FAQ-Xt It's not name mangling causing problems, it's lack of "this" when the method is invoked as a callback from Xt. Yes! This is the method! I like it, or at least, it's as close (in C++ code) to something I do like. Thanks very much, Ted. Nice catch. -Ted Chuck Robey| Interests include C programming, Electronics, 213 Lakeside Dr. Apt. T-1 | communications, and signal processing. Greenbelt, MD 20770| I run picnic.mat.net: FreeBSD-current(i386) and (301) 220-2114 | jaunt.mat.net : FreeBSD-current(Alpha) To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
Allow me add something to what the FAQ-Xt says.
I find it more convenient to immediately call a non-static
function as shown below (using a slightly modified example
from the FAQ).
class Icon {
public:
Icon(Widget*);
private:
static void static_callback(Icon*);
inline void real_callback();
Widget* button;
int count;
...
};
Icon::Icon(Widget* parent): count(0)
{
button = XtVaCreateWidget("Boo!", xmPushButtonWidgetClass, parent, 0);
XtAddCallback(button, XmNselectCallback, Icon::static_callback,
(XtPointer)this);
...
}
inline void
Icon::real_callback()
{
count++;
...
}
void
Icon::static_callback(Icon* icon)
{
icon-real_callback();
}
The reason for calling real_callback from static_callback is
to avoid having to specify icon-count etc. to reference
components of the Icon object. This makes a difference in
readability if your callback function does a bunch of stuff.
The reason for inlining to not incur the cost of an
additional call (if this matters -- usually it doesn't).
Inlining can get in your way during debugging (atleast gdb
loses its mind) so provide a way to disable it. BTW, this
idiom is useful pretty much any time you have to use C++
callbacks from C code, not just for X11.
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Re: X11/C++ question
On Tue, 26 Oct 1999, Bakul Shah wrote: Allow me add something to what the FAQ-Xt says. I find it more convenient to immediately call a non-static function as shown below (using a slightly modified example from the FAQ). Just got out of the shower, where I was wondering why they didn't suggest the same thing. I was going to experiment with this way, since it fit more closely with the way I like to code C++ (I don't like to code C++, you understand, so my C++ code is always straining to look like C). Thanks, Bakul. This looks much better. Thanks, folks, for letting me pull hackers away from FreeBSD for a minute, but let's not let it get out of hand; we better stop before we strain other's patience. Chuck Robey| Interests include C programming, Electronics, 213 Lakeside Dr. Apt. T-1 | communications, and signal processing. Greenbelt, MD 20770| I run picnic.mat.net: FreeBSD-current(i386) and (301) 220-2114 | jaunt.mat.net : FreeBSD-current(Alpha) To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: X11/C++ question
On Tue, 26 Oct 1999, Chris Costello wrote:
On Tue, Oct 26, 1999, Thomas David Rivers wrote:
extern "C" {
void
callback_function(arg1)
void *arg1;
{
/* Call the method */
myclass::mymethod(arg1);
As far as I've seen, you can't directly call a class method
without an object.
Sure you can. It won't have any access to "this" or any part thereof,
however.
--
|Chris Costello [EMAIL PROTECTED]
|A closed mouth gathers no feet.
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