This code has been changed since I last compiled it on Z but I don't think I changed that reference. It appears that PATH_MAX went away somewhere between V2R2 and V2R4. I see some comments in limits.h that are consistent with that.
I picked up _POSIX_PATH_MAX from limits.h. I am running POSIX(ON). It that a valid maximum path length or am I likely to get whacked with a buffer overflow? Re-stating the question, what is the maximum path length on z/OS UNIX? Can it really be true that there is no hard maximum? I really have to ask pathconf() every time? No maximum of possible maximums? The maximum is really whatever z/OS wants it to be today? What is FILENAME_MAX, referenced in https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.4.0/com.ibm.zos.v2r4.bpxbd00/fldata.htm ? Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Paul Gilmartin Sent: Wednesday, December 2, 2020 3:25 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: C macro for maximum path length? On Wed, 2 Dec 2020 15:16:10 -0800, Charles Mills wrote: >I have some code that compiles both under Windows Visual Studio and z/OS >XLC. > >In Windows the maximum length of a file path is defined by _MAX_PATH and >__MAX_PATH (I guess MS thinks two macros are better than one). > >What is the equivalent macro for XLC? Failing that, what *is* the maximum >path length so I can define my own macro? > >Posix defines PATH_MAX and I see references to it in the z/OS doc but it >does not seem to be defined for my compile. How do I pick that up? And yes, >I have > >#define _XOPEN_SOURCE_EXTENDED 1 >#include <stdlib.h> > PATH_MAX is deprecated (I thought even by POSIX). IBM says this it is because the value differs among filesystems. Here is some code where I used the recommended alternative in a call to realpath(). (realpath() is dreadful: an invitation to buffer overflows.) /* ***************************************** */ /* Doc: Print the resolved pathname of each argument */ #include <stdlib.h> #include <stdio.h> #include <limits.h> #include <unistd.h> #undef PATH_MAX int main( int argc, char ** argv ) { char **file_name; int status=0; for ( file_name = argv; *++file_name; ) { long PATH_MAX; if ( ( PATH_MAX = pathconf( *file_name, _PC_PATH_MAX ) )>0 ) { char *resolved_name; if ( resolved_name = malloc( PATH_MAX + 1 ) ); { if ( realpath( *file_name, resolved_name ) ) { printf( "%s\n", resolved_name ); free( resolved_name ); continue; } free( resolved_name ); } } perror( *file_name ); status = 1; } exit( status ); } ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
