This is another small request for review:
Size of patch: 2/7
Complexity: 1/7
-Brad
-----
Change the return type of is_c_nil from c_int to bool
This commit changes the return type of is_c_nil from c_int to bool. I
reviewed the concept with Michael (who write is_c_nil() originally) before
implementing. I believe that is_c_nil returns a c_int simply because it
was wrapping a C comparison operator that returns an int; making it a bool
seems more natural for Chapel's sake and removes a case where we rely on C
types in something that an end-user or library writer might want to use.
I implemented this by casting the result to chpl_bool in the C routine
that implements c_is_bool(). To do this, I had to move the definition of
chpl_bool up in the file.
I added a test to lock in this capability.
The reason I ran into this is that I was writing code of the form:
if (!is_c_nil(x))
only to find that it wouldn't work due to our lack of support for ! on int
types, which led me to be surprised that is_c_nil returned an int. In
another patch, I've extended support of ! to include integers; this commit
solves the issue in a different way.
I also simplified existing expressions that use is_c_nil() based on this
change.
Note for discussion: I think I would've called Chapel's notion of 'NULL'
'c_NULL' rather than 'c_nil', much like we call C's 'double' 'c_double'
rather than 'c_real'. Put another way, I worry that a C programmer using
Chapel would not find/guess 'c_nil' as quickly as they would 'c_NULL'.
Thoughts?Index: test/studies/filerator/listdir.chpl
===================================================================
--- test/studies/filerator/listdir.chpl (revision 23710)
+++ test/studies/filerator/listdir.chpl (working copy)
@@ -21,9 +21,9 @@
var ent: direntptr;
// writeln("***Trying ", path);
dir = opendir(path:c_string);
- if (is_c_nil(dir) == 0) {
+ if (!is_c_nil(dir)) {
ent = readdir(dir);
- while (is_c_nil(ent) == 0) {
+ while (!is_c_nil(ent)) {
const filename = ent.d_name();
if (dotfiles || filename.substring(1) != '.') {
const fullpath = path + "/" + filename;
Index: test/extern/bradc/externNull.good
===================================================================
--- test/extern/bradc/externNull.good (revision 0)
+++ test/extern/bradc/externNull.good (revision 0)
@@ -0,0 +1,2 @@
+true
+false
Index: test/extern/bradc/externNull.chpl
===================================================================
--- test/extern/bradc/externNull.chpl (revision 0)
+++ test/extern/bradc/externNull.chpl (revision 0)
@@ -0,0 +1,6 @@
+extern type sPtr;
+extern proc getNullSPtr(): sPtr;
+extern proc getNonNullSPtr(): sPtr;
+
+writeln(is_c_nil(getNullSPtr()));
+writeln(is_c_nil(getNonNullSPtr()));
Index: test/extern/bradc/externNull.h
===================================================================
--- test/extern/bradc/externNull.h (revision 0)
+++ test/extern/bradc/externNull.h (revision 0)
@@ -0,0 +1,15 @@
+typedef struct _s {
+ double x;
+} s;
+
+typedef s* sPtr;
+
+s myS;
+
+static inline sPtr getNullSPtr(void) {
+ return NULL;
+}
+
+static inline sPtr getNonNullSPtr(void) {
+ return &myS;
+}
Index: test/extern/bradc/externNull.compopts
===================================================================
--- test/extern/bradc/externNull.compopts (revision 0)
+++ test/extern/bradc/externNull.compopts (revision 0)
@@ -0,0 +1 @@
+externNull.h
Index: runtime/include/chpltypes.h
===================================================================
--- runtime/include/chpltypes.h (revision 23710)
+++ runtime/include/chpltypes.h (working copy)
@@ -23,8 +23,16 @@
typedef float c_float;
typedef double c_double;
typedef void* c_void_ptr;
+
+// C++ does not support c99 bools
+#ifndef __cplusplus
+typedef _Bool chpl_bool;
+#else
+typedef bool chpl_bool;
+#endif
+
#define c_nil NULL
-static inline c_int is_c_nil(void* x) { return x==NULL; }
+static inline c_int is_c_nil(void* x) { return (chpl_bool)(x==NULL); }
static inline void* c_pointer_return(void* x) { return x; }
typedef enum {
@@ -148,13 +156,6 @@
#define UINT64( i) ((uint64_t)(UINT64_C(i)))
-// C++ does not support c99 bools
-#ifndef __cplusplus
-typedef _Bool chpl_bool;
-#else
-typedef bool chpl_bool;
-#endif
-
typedef int8_t chpl_bool8;
typedef int16_t chpl_bool16;
typedef int32_t chpl_bool32;
Index: modules/standard/IO.chpl
===================================================================
--- modules/standard/IO.chpl (revision 23710)
+++ modules/standard/IO.chpl (working copy)
@@ -531,7 +531,7 @@
}
proc file.check() {
- if(1 == is_c_nil(_file_internal)) {
+ if(is_c_nil(_file_internal)) {
halt("Operation attempted on an invalid file");
}
}
Index: modules/standard/SysBasic.chpl
===================================================================
--- modules/standard/SysBasic.chpl (revision 23710)
+++ modules/standard/SysBasic.chpl (working copy)
@@ -38,7 +38,7 @@
// To generate legal C prototypes, we have to manually instantiate this
// prototype for each pointer type that might be associated with 'x'.
pragma "no prototype"
-extern proc is_c_nil(x):c_int;
+extern proc is_c_nil(x):bool;
// local C pointer class used in C integration.
// Similar to _ddata from ChapelBase, but differs
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