How can I write a file with mmap in C?
Here’s an example of writing to a file using mmap.
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <string.h>
int main(void) {
int fd = open("test_file", O_RDWR | O_CREAT, (mode_t)0600);
const char *text = "hello";
size_t textsize = strlen(text) + 1;
lseek(fd, textsize-1, SEEK_SET);
write(fd, "", 1);
char *map = mmap(0, textsize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
memcpy(map, text, strlen(text));
msync(map, textsize, MS_SYNC);
munmap(map, textsize);
close(fd);
return 0;
}
Tagged . All content copyright James Fisher 2017. This post is not associated with my employer.
TigYog