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Truncates a file to a given length
(PHP 4, PHP 5)
Related Examples ( Source code ) » ftruncate Examples ( Source code ) » Simple Google Site Map Generator Code Examples / Notes » ftruncatemike
I have produced a number of tests below which walk through my findings of the ftruncate function. For the impatient among you ftruncate can be used to increase the size of the file and will fill the rest of the file with CHR 0 or ASCII NULL. It can be used as a very convenient way of making a 1Mb file for instance. Test 1 <?php /* Test 1: Write "some text" to a file. Result: The text "some text" should be present in test_1.txt */ $fp = fopen('test_1.txt', 'w+'); fwrite($fp, 'some text'); ?> The first test is only here to make sure that a file can be written with some text. Test 2 <?php /* Test 2: Write "some text" to a file and ftruncate the file to 4 bytes. Result: The text "some" should be present in test_2.txt as the file will have been truncated to 4 bytes. */ $fp = fopen('test_2.txt', 'w+'); fwrite($fp, 'some text'); ftruncate($fp, 4); ?> As expected the file has been truncated to 4 bytes. Test 3 <?php /* Test 3: Write "some text" to a file and ftruncate the file to 40 bytes. Result: The text "some text" should be present in test_3.txt as the file will have been truncated to 40 bytes. */ $fp = fopen('test_3.txt', 'w+'); fwrite($fp, 'some text'); ftruncate($fp, 40); ?> Interestingly the file has increased from 9 bytes to 40 bytes. The remaining 31 bytes of the file are ASCII code 0 or NULL though. Further notes can be found here http://mikeleigh.com/links/ftruncate |
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basename chgrp chmod chown clearstatcache copy delete dirname disk_free_space disk_total_space diskfreespace fclose feof fflush fgetc fgetcsv fgets fgetss file_exists file_get_contents file_put_contents file fileatime filectime filegroup fileinode filemtime fileowner fileperms filesize filetype flock fnmatch fopen fpassthru fputcsv fputs fread fscanf fseek fstat ftell ftruncate fwrite glob is_dir is_executable is_file is_link is_readable is_uploaded_file is_writable is_writeable lchgrp lchown link linkinfo lstat mkdir move_uploaded_file parse_ini_file pathinfo pclose popen readfile readlink realpath rename rewind rmdir set_file_buffer stat symlink tempnam tmpfile touch umask unlink |
