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| /* This is a test case where the parent process forks 10
* children which contend to write to the same file. With
* file locking support, the data from each child should not
* be lost.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
extern FILE *lprofOpenFileEx(const char *);
int main(int argc, char *argv[]) {
pid_t tid;
FILE *F;
const char *FN;
int child[10];
int c;
int i;
if (argc < 2) {
fprintf(stderr, "Requires one argument \n");
exit(1);
}
FN = argv[1];
truncate(FN, 0);
for (i = 0; i < 10; i++) {
c = fork();
// in child:
if (c == 0) {
FILE *F = lprofOpenFileEx(FN);
if (!F) {
fprintf(stderr, "Can not open file %s from child\n", FN);
exit(1);
}
fseek(F, 0, SEEK_END);
fprintf(F, "Dump from Child %d\n", i);
fclose(F);
exit(0);
} else {
child[i] = c;
}
}
// In parent
for (i = 0; i < 10; i++) {
int child_status;
if ((tid = waitpid(child[i], &child_status, 0)) == -1)
break;
}
F = lprofOpenFileEx(FN);
if (!F) {
fprintf(stderr, "Can not open file %s from parent\n", FN);
exit(1);
}
fseek(F, 0, SEEK_END);
fprintf(F, "Dump from parent %d\n", i);
return 0;
}
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