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→{{header|C}}: more specific error messages
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}</lang>
=== Using mmap() ===
Implementation using mmap syscall. Works on Linux 2.6.*, should work on *BSDs (they invented mmap, after all). Line reading routine takes a callback function, each line is passed into callback as begin and end pointer. Let OS handle your memory pages, we don't need no stinking mallocs.
<lang C>#include <stdio.h>
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if (fd == -1) {
err(1, "open: %s", fname);
return 0;
}
if (fstat(fd, &fs) == -1) {
err(1, "stat: %s", fname);
return 0;
}
/* fs.st_size could have been 0 actually */
buf = mmap(0, fs.st_size, PROT_READ, MAP_SHARED, fd, 0);
if (buf == (void*) -1) {
err(1, "mmap: %s", fname);
return 0;
}
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begin = end = buf;
while (
if (! (*end == '\r' || *end == '\n')) {
if (++end < buf_end) continue;
} else if (1 + end < buf_end)
▲ }
if (1 + end < buf_end) {▼
/* see if we got "\r\n" or "\n\r" here */
c = *(1 + end);
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/* call the call back and check error indication. Announce
error here, because we didn't tell
*/▼
if (! call_back(begin, end)) {
break;
}
if ((begin = ++end
}
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int print_line(char* begin, char* end)
{
return 0;
return 1;
}
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int main()
{
return read_lines("
}
</lang>
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