Is Fseek fast?
is very fast. Now if you uncomment the line that says fseek(fp, 0, SEEK_CUR), it runs 17x slower!
Is fwrite fast?
fwrite on its own is generally the fastest although the buffered version can sometimes beat it if you get the size and iterations just right. Asynchronous writes were not significantly better than the buffered version.
Is write faster than fwrite?
For small (e.g., line-at-a-time) byte counts, fwrite (3) is faster, because of the overhead for just doing a kernel call. For large (block I/O) byte counts, write (2) is faster, because it doesn’t bother with buffering and you have to call the kernel in both cases.
What is the difference between write and fwrite?
fwrite writes to a FILE* , i.e. a (potentially) buffered stdio stream. It’s specified by the ISO C standard. Additionally, on POSIX systems, fwrite is thread-safe to a certain degree. write is a lower-level API based on file descriptors, described in the POSIX standard.
Can Fseek offset be negative?
The value of offset must not be negative. SEEK_CUR. The new file position is computed relative to the current file position. The fseek() function clears the end-of-file indicator, and undoes any effects of the ungetc() function on the same file.
What does Fseek return?
Return Value. The fseek() or fseeko() function returns 0 if it successfully moves the pointer. A nonzero return value indicates an error. On devices that cannot seek, such as terminals and printers, the return value is nonzero.
Is Fwrite buffered?
Yes, it is buffered. The size of the buffer is defined by BUFSIZ .
Is Fwrite thread safe?
fwrite() is a function that writes to a FILE*, which is a (possibly) buffered stdio stream. The ISO C standard specifies it. Furthermore, fwrite() is thread-safe to a degree on POSIX platforms.
Is fwrite thread safe?
What does read () do in C?
The read() function reads data previously written to a file. If any portion of a regular file prior to the end-of-file has not been written, read() shall return bytes with value 0.
What can I use instead of Fseek?
We recommend that you use the ANSI standard functions “fsetpos” and “fgetpos” instead of “fseek” and “ftell”. The reason is that “fseek” and “ftell” only use a long integer (36 bits) to represent a position in a file; this is not adequate to deal with all the positions in a large GCOS8 file.
What is Fseek in C?
fseek() is used to move file pointer associated with a given file to a specific position. Syntax: int fseek(FILE *pointer, long int offset, int position) pointer: pointer to a FILE object that identifies the stream. offset: number of bytes to offset from position position: position from where offset is added.