c - type checking across source files -

i spent many hours debugging problem turned out caused 2 source files including 2 header files in different order. 1 of headers defined _file_offset_bits 64, , other header file included <sys/types.h>, defined off_t either 32 or 64 bits long, depending on setting of _file_offset_bits. i've included below short example of situation. on x86_32 linux (both debian unstable , centos 4.8).

neither gcc -wall main.c other.c, nor solaris 9 lint, nor splint detects situation.

does know of software tool can detect situation?

main.c

 #define _file_offset_bits 64 #include <sys/types.h> #include <stdio.h>  #include "header.h"  int main(int argc, char **argv) {         struct foo bar = {(off_t) 0, "foo"};          showproc(&bar);         printf("sizeof(off_t) in main.c %d\n", sizeof(off_t));          return 0; } 

other.c

 #include <sys/types.h> #define _file_offset_bits 64 #include <stdio.h>  #include "header.h"  void showproc(const struct foo *p) {         if (p->offset == 0) {             if (p->s == null)                 puts("null pointer reference");             else                 printf("structure value %s\n", p->s);         }         printf("sizeof(off_t) in other.c %d\n", sizeof(off_t)); } 

header.h

 struct foo {         off_t           offset;         const char *    s; };  extern void showproc(const struct foo *); 

program output

 null pointer reference sizeof(off_t) in other.c 4 sizeof(off_t) in main.c 8 

i recommend putting defines modify headers in makefile instead of in code. otherwise can't sure compilation units have 1 definition or other, you've experienced.

sometimes modifying headers macros intended behavior (e.g. using headers templates) , isn't (like in case), hard produce meaningful warnings tool, think.