init

Makefile

+CC = gcc
+
+all: workdir.c print_file.c
+	${CC} -o workdir workdir.c
+	${CC} -o print_file print_file.c
+
+clean:
+	rm -f workdir print_file

print_file.c

+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+
+#define SIZE 512
+
+int main() {
+
+  int fd = open("./test.txt", O_RDWR); 
+  if (fd == -1){
+    perror("could not open file");
+    return EXIT_FAILURE;
+  }
+
+  char * buffer = (char *) calloc(SIZE, sizeof(char)); 
+
+  ssize_t r = read(fd, buffer, SIZE-1); 
+  if (r == -1) {
+    perror("could not read file");
+    free(buffer);
+    close(fd);
+    return EXIT_FAILURE;
+  }
+
+  printf("%.*s", SIZE-1, buffer);
+  free(buffer);
+  close(fd);
+  return EXIT_SUCCESS;
+}

workdir.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+char *mywdfunc(unsigned int bufsize) {
+  if (bufsize < 100) {
+    return NULL;
+  }
+
+  char *buf = (char *)calloc(bufsize,sizeof(char));
+  if (buf) {
+    getcwd(buf,bufsize-1);
+  }
+
+  return buf; 
+}
+
+int main() {
+
+  char *ret = mywdfunc(512);
+
+  printf("%s", ret);
+  free(ret);
+  return EXIT_SUCCESS;
+}