File input/output - cppreference.com (original) (raw)
The <stdio.h> header provides generic file operation support and supplies functions with narrow character input/output capabilities.
The <wchar.h> header supplies functions with wide character input/output capabilities.
I/O streams are denoted by objects of type FILE that can only be accessed and manipulated through pointers of type FILE*. Each stream is associated with an external physical device (file, standard input stream, printer, serial port, etc).
Contents
[edit] Types
[edit] Predefined standard streams
[edit] Functions
| File access | |
|---|---|
| Defined in header <stdio.h> | |
| fopenfopen_s(C11) | opens a file (function) [edit] |
| freopenfreopen_s(C11) | open an existing stream with a different name (function) [edit] |
| fclose | closes a file (function) [edit] |
| fflush | synchronizes an output stream with the actual file (function) [edit] |
| setbuf | sets the buffer for a file stream (function) [edit] |
| setvbuf | sets the buffer and its size for a file stream (function) [edit] |
| Defined in header <wchar.h> | |
| fwide(C95) | switches a file stream between wide character I/O and narrow character I/O (function) [edit] |
| Direct input/output | |
| Defined in header <stdio.h> | |
| fread | reads from a file (function) [edit] |
| fwrite | writes to a file (function) [edit] |
| Unformatted input/output | |
| Narrow character | |
| Defined in header <stdio.h> | |
| fgetcgetc | gets a character from a file stream (function) [edit] |
| fgets | gets a character string from a file stream (function) [edit] |
| fputcputc | writes a character to a file stream (function) [edit] |
| fputs | writes a character string to a file stream (function) [edit] |
| getchar | reads a character from stdin (function) [edit] |
| getsgets_s(removed in C11)(C11) | reads a character string from stdin (function) [edit] |
| putchar | writes a character to stdout (function) [edit] |
| puts | writes a character string to stdout (function) [edit] |
| ungetc | puts a character back into a file stream (function) [edit] |
| Wide character | |
| Defined in header <wchar.h> | |
| fgetwcgetwc(C95) | gets a wide character from a file stream (function) [edit] |
| fgetws(C95) | gets a wide string from a file stream (function) [edit] |
| fputwcputwc(C95) | writes a wide character to a file stream (function) [edit] |
| fputws(C95) | writes a wide string to a file stream (function) [edit] |
| getwchar(C95) | reads a wide character from stdin (function) [edit] |
| putwchar(C95) | writes a wide character to stdout (function) [edit] |
| ungetwc(C95) | puts a wide character back into a file stream (function) [edit] |
| Formatted input/output | |
| Narrow character | |
| Defined in header <stdio.h> | |
| scanffscanfsscanfscanf_sfscanf_ssscanf_s(C11)(C11)(C11) | reads formatted input from stdin, a file stream or a buffer (function) [edit] |
| vscanfvfscanfvsscanfvscanf_svfscanf_svsscanf_s(C99)(C99)(C99)(C11)(C11)(C11) | reads formatted input from stdin, a file stream or a buffer using variable argument list (function) [edit] |
| printffprintfsprintfsnprintfprintf_sfprintf_ssprintf_ssnprintf_s(C99)(C11)(C11)(C11)(C11) | prints formatted output to stdout, a file stream or a buffer (function) [edit] |
| vprintfvfprintfvsprintfvsnprintfvprintf_svfprintf_svsprintf_svsnprintf_s(C99)(C11)(C11)(C11)(C11) | prints formatted output to stdout, a file stream or a buffer using variable argument list (function) [edit] |
| Wide character | |
| Defined in header <wchar.h> | |
| wscanffwscanfswscanfwscanf_sfwscanf_sswscanf_s(C95)(C95)(C95)(C11)(C11)(C11) | reads formatted wide character input from stdin, a file stream or a buffer (function) [edit] |
| vwscanfvfwscanfvswscanfvwscanf_svfwscanf_svswscanf_s(C99)(C99)(C99)(C11)(C11)(C11) | reads formatted wide character input from stdin, a file stream or a buffer using variable argument list (function) [edit] |
| wprintffwprintfswprintfwprintf_sfwprintf_sswprintf_ssnwprintf_s(C95)(C95)(C95)(C11)(C11)(C11)(C11) | prints formatted wide character output to stdout, a file stream or a buffer (function) [edit] |
| vwprintfvfwprintfvswprintfvwprintf_svfwprintf_svswprintf_svsnwprintf_s(C95)(C95)(C95)(C11)(C11)(C11)(C11) | prints formatted wide character output to stdout, a file stream or a buffer using variable argument list (function) [edit] |
| File positioning | |
| Defined in header <stdio.h> | |
| ftell | returns the current file position indicator (function) [edit] |
| fgetpos | gets the file position indicator (function) [edit] |
| fseek | moves the file position indicator to a specific location in a file (function) [edit] |
| fsetpos | moves the file position indicator to a specific location in a file (function) [edit] |
| rewind | moves the file position indicator to the beginning in a file (function) [edit] |
| Error handling | |
| Defined in header <stdio.h> | |
| clearerr | clears errors (function) [edit] |
| feof | checks for the end-of-file (function) [edit] |
| ferror | checks for a file error (function) [edit] |
| perror | displays a character string corresponding of the current error to stderr (function) [edit] |
| Operations on files | |
| Defined in header <stdio.h> | |
| remove | erases a file (function) [edit] |
| rename | renames a file (function) [edit] |
| tmpfiletmpfile_s(C11) | returns a pointer to a temporary file (function) [edit] |
| tmpnamtmpnam_s(C11) | returns a unique filename (function) [edit] |
[edit] Macro constants
| Defined in header <stdio.h> | |
|---|---|
| EOF | integer constant expression of type int and negative value (macro constant) |
| FOPEN_MAX | maximum number of files that can be open simultaneously (macro constant) |
| FILENAME_MAX | size needed for an array of char to hold the longest supported file name (macro constant) |
| BUFSIZ | size of the buffer used by setbuf (macro constant) |
| _IOFBF_IOLBF_IONBF | argument to setvbuf indicating fully buffered I/Oargument to setvbuf indicating line buffered I/Oargument to setvbuf indicating unbuffered I/O (macro constant) |
| SEEK_SETSEEK_CURSEEK_END | argument to fseek indicating seeking from beginning of the fileargument to fseek indicating seeking from the current file positionargument to fseek indicating seeking from end of the file (macro constant) |
| TMP_MAXTMP_MAX_S(C11) | maximum number of unique filenames that can be generated by tmpnammaximum number of unique filenames that can be generated by tmpnam_s (macro constant) |
| L_tmpnamL_tmpnam_s(C11) | size needed for an array of char to hold the result of tmpnamsize needed for an array of char to hold the result of tmpnam_s (macro constant) |
[edit] References
C23 standard (ISO/IEC 9899:2024):
7.21 Input/output <stdio.h> (p: TBD)
7.29 Extended multibyte and wide character utilities <wchar.h> (p: TBD)
7.31.11 Input/output <stdio.h> (p: TBD)
7.31.16 Extended multibyte and wide character utilities <wchar.h> (p: TBD)
K.3.5 Input/output <stdio.h> (p: TBD)
C17 standard (ISO/IEC 9899:2018):
7.21 Input/output <stdio.h> (p: TBD)
7.29 Extended multibyte and wide character utilities <wchar.h> (p: TBD)
7.31.11 Input/output <stdio.h> (p: TBD)
7.31.16 Extended multibyte and wide character utilities <wchar.h> (p: TBD)
K.3.5 Input/output <stdio.h> (p: TBD)
C11 standard (ISO/IEC 9899:2011):
7.21 Input/output <stdio.h> (p: 296-339)
7.29 Extended multibyte and wide character utilities <wchar.h> (p: 402-446)
7.31.11 Input/output <stdio.h> (p: 456)
7.31.16 Extended multibyte and wide character utilities <wchar.h> (p: 456)
K.3.5 Input/output <stdio.h> (p: 586-603)
C99 standard (ISO/IEC 9899:1999):
7.19 Input/output <stdio.h> (p: 262-305)
7.24 Extended multibyte and wide character utilities <wchar.h> (p: 348-392)
7.26.9 Input/output <stdio.h> (p: 402)
7.26.12 Extended multibyte and wide character utilities <wchar.h> (p: 402)
C89/C90 standard (ISO/IEC 9899:1990):
4.9 INPUT/OUTPUT <stdio.h>
4.13.6 Input/output <stdio.h>