ch7. process environment

◆ exit

 

#include<stdlib.h>

 void exit(int status);

 

 

◆ _Exit

 

#include<stdlib.h>

 void _Exit(int status);

 

◆ _exit

 

#include<unistd.h>

 void _exit(int status);

 

◆ atexit

#include<stdlib.h>

 int atexit(void (*func) (void));

 

 

#include<stdio.h> #include<stdlib.h> static void my_exit1(void); static void my_exit2(void); int main(void) { if (atexit(my_exit2) != 0) { printf("can't register my_exit2\n"); exit(1); } if(atexit(my_exit1) != 0) { printf("can't register my_exit1\n"); exit(1); } if(atexit(my_exit1) != 0) { printf("can't register my_exit1\n"); exit(1); } printf("main is done\n"); return 0; } static void my_exit1(void) { printf("first exit handler\n"); } static void my_exit2(void) { printf("second exit handle\n"); }

 

#include<stdio.h> #include<stdlib.h> int main(int argc, char *argv[]) { int i; for( i=0 ; i<argc ; i++) { printf("argv[%3d]: %s\n",i,argv[i]); } exit(0); }

 

 

 

◆ malloc

#include<stdlib.h>

 void* malloc(size_t size);

(ret)  success : NULL이 아닌 포인터

   failed : NULL

◆ calloc

#include<stdlib.h>

 void* calloc(size_t nobj, size_t size);

(ret)  success : NULL이 아닌 포인터

   failed : NULL

◆ realloc

#include<stdlib.h>

 void *realloc(void *ptr, size_t newsize);

(ret)  success : NULL이 아닌 포인터

   failed : NULL

◆ free

#include<stdlib.h>

 void free(void *ptr);

 

 

◆ getenv

#include<stdlib.h>

 char* getenv(const char *name);

(ret)  success : name으로 주어진 이름에 해당하는 환경 변수값을 가리키는 포인터

   failed : 이름이 없는 경우 NULL

◆ putenv

#include<stdlib.h>

 int putenv(char *str);

(ret)  success : 0

   failed : 0이 아닌 값

◆ setenv

#include<stdlib.h>

 int setenv(const char *name, const char *value, int rewrite);

(ret)  success : 0

   failed : -1

◆ unsetenv

#include<stdlib.h>

 int unsetenv(const char *name);

(ret)  success : 0

   failed : -1

◆ setjmp

#include<setjmp.h>

 int setjmp(jmp_buf env);

(ret)  직접 호출돈 경우에는 0, longjmp를 통해서 호출된 경우에는 0이 아닌 값

◆ longjmp

#include<setjmp.h>

 void longjmp(jmp_buf env, int val);

 

 

#include<stdio.h> #include<stdlib.h> #include<setjmp.h> static void f1(int, int, int, int); static void f2(void); static jmp_buf jmpbuffer; static int globval; int main(void) { int autoval; register int regival; volatile volaval; static int statval; globval = 1; autoval = 2; regival = 3; volaval = 4; statval = 5; if(setjmp(jmpbuffer) != 0) { printf("After longjmp :\n"); printf("globval = %d, autoval = %d, regival = %d," "volaval = %d, statval = %d\n", globval, autoval, regival, volaval, statval); exit(0); } globval = 95; autoval = 96; regival = 97; volaval = 98; statval = 99; f1(autoval, regival, volaval, statval); exit(0); } static void f1(int i, int j, int k, int l) { printf("in f1():\n"); printf("globval = %d, autoval = %d, regival = %d," "volaval = %d, statval = %d\n", globval, i,j,k,l); f2(); } static void f2(void) { longjmp(jmpbuffer, 1); }

 

 

 

 

◆ getrlimit

#include<setjmp.h>

 int getrlimit(int resource, struct rlimit *rlptr);

(ret)  success : 0

   failed : 0이 아닌 값

◆ setrlimit

#include<setjmp.h>

 int setrlimit(int resource, const struct rlimit *rlptr);

(ret)  success : 0

   failed : 0이 아닌 값

#include<stdio.h> #include<stdlib.h> #if defined(BSD) || defined(MACOS) #include<sys/time.h> #define FMT "%10lld " #else #define FMT "%10ld" #endif #include<sys/resource.h> #define doit(name) pr_limits(#name, name); static void pr_limits(char *, int); int main(void) { #ifdef RLIMIT_AS doit(RLIMIT_AS); #endif doit(RLIMIT_CORE); doit(RLIMIT_CPU); doit(RLIMIT_DATA); doit(RLIMIT_FSIZE); #ifdef RLIMIT_LOCKS doit(RLIMIT_LOCKS); #endif #ifdef RLIMIT_MEMLOCK doit(RLIMIT_MEMLOCK); #endif doit(RLIMIT_NOFILE); #ifdef RLIMIT_NPROC doit(RLIMIT_NPROC); #endif #ifdef RLIMIT_RSS doit(RLIMIT_RSS); #endif #ifdef RLIMIT_SBSIZE doit(RLIMIT_SBSIZE); #endif doit(RLIMIT_STACK); #ifdef RLIMIT_VMEM doit(RLIMIT_VMEM); #endif exit(0); } static void pr_limits(char *name, int resource) { struct rlimit limit; if(getrlimit(resource, &limit) < 0) { printf("getrlimit error for %s\n",name); exit(1); } printf("%-14s ",name); if(limit.rlim_cur == RLIM_INFINITY) printf("(infinite) "); else printf(FMT, limit.rlim_cur); if(limit.rlim_max == RLIM_INFINITY) printf(" (infinite) "); else printf(FMT, limit.rlim_max); putchar((int) '\n'); }