C language standard IO function sorting

Catalog

One 、 brief introduction

Two 、 Common standards IO function

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One 、 brief introduction

common IO Functions fall into two categories , They are standard IO And system IO, The specific differences and connections are ：

• Systems of different systems IO There's a difference , And the standard IO It is common to any platform ;
• standard IO Is dependent on system calls IO Realized ;
• standard IO Large throughput , file IO Fast response ;
• standard IO And documents IO Don't mix .

Two 、 Common standards IO function

FIFE *fopen(const char *path, const char *mode);
/*
path:  Open file path 
mode:  Open file mode 
*/

int fclose(FIFE *stream)
//  Close the current file stream 

int fgetc(FIFE *stream)
//  Read a character , Returns the character converted to int Type value 

int fputc(int c, FIFE *stream);
//  hold c Convert to the corresponding character , writes stream in 

char *fgets(char *s, int size, FIFE *stream);
//  Read line breaks or EOF end , The results are saved to s in , Will save one more '\0'

int fputs(const char *s, FIFE *stream);
//  hold s remove '\0' Characters other than write stream in 

size_t fread(void *ptr, size_t size, size_t nmemb, FIFE *stream);
//  read nmemb Elements , Each size size byte , Save to ptr in 

size_t fwrite(const void *ptr, size_t size, size_t nmemb, FIFE *stream);
//  Write nmemb Elements , Each size size byte , writes stream in 

//  File location pointer related ：
int fseek(FIFE *stream, long offset, int whence)
long ftell(FIFE *stream)
void rewind(FIFE *stream)
int fflush(FIFE *stream)

// printf/scanf gens 
int printf(const char *format);
int fprintf(FIFE *stream, const char *format, ...);
int sprintf(char *str, const  char *format, ...);   // It can be seen as atoi The inverse function of 
//sprintf() May cause buffer overflow 
int snprintf(char *str, size_t size, const char *format, ...);  

int scanf(const char *format, ...);\
int fscanf(FILE *stream, const char *format, ...);
int sscanf(const char *str, const char* format, ...);

• fread() and fwrite() It is only suitable for reading and writing neat byte blocks ;
• fseek() and ftell It can only be used when the file size does not exceed 2G Of .