求C語言中的庫函數(shù)的源代碼 如printf()函數(shù)，我要它的源代碼

如果你安裝的Visual Studio，以及它的Visual C++的話，

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那么在安裝目錄下的VC/crt/src下有所有標準C庫的源代碼

另外，h后綴的頭文件包含函數(shù)的聲明，具體的實現(xiàn)都在c后綴的源碼文件中

C語言中對字符串進行操作的標準庫函數(shù)有哪些

1）字符串操作

strcpy(p, p1) 復制字符串

strncpy(p, p1, n) 復制指定長度字符串

strcat(p, p1) 附加字符串

strncat(p, p1, n) 附加指定長度字符串

strlen(p) 取字符串長度

strcmp(p, p1) 比較字符串

strcasecmp忽略大小寫比較字符串

strncmp(p, p1, n) 比較指定長度字符串

strchr(p, c) 在字符串中查找指定字符

strrchr(p, c) 在字符串中反向查找

strstr(p, p1) 查找字符串

strpbrk(p, p1) 以目標字符串的所有字符作為集合，在當前字符串查找該集合的任一元素

strspn(p, p1) 以目標字符串的所有字符作為集合，在當前字符串查找不屬于該集合的任一元素的偏移

strcspn(p, p1) 以目標字符串的所有字符作為集合，在當前字符串查找屬于該集合的任一元素的偏移

* 具有指定長度的字符串處理函數(shù)在已處理的字符串之后填補零結(jié)尾符

2）字符串到數(shù)值類型的轉(zhuǎn)換

strtod(p, ppend) 從字符串 p 中轉(zhuǎn)換 double 類型數(shù)值，并將后續(xù)的字符串指針存儲到 ppend 指向的 char* 類型存儲。

strtol(p, ppend, base) 從字符串 p 中轉(zhuǎn)換 long 類型整型數(shù)值，base 顯式設(shè)置轉(zhuǎn)換的整型進制，設(shè)置為 0 以根據(jù)特定格式判斷所用進制，0x, 0X 前綴以解釋為十六進制格式整型，0 前綴以解釋為八進制格式整型

atoi(p) 字符串轉(zhuǎn)換到 int 整型

atof(p) 字符串轉(zhuǎn)換到 double 符點數(shù)

atol(p) 字符串轉(zhuǎn)換到 long 整型

3）字符檢查

isalpha() 檢查是否為字母字符

isupper() 檢查是否為大寫字母字符

islower() 檢查是否為小寫字母字符

isdigit() 檢查是否為數(shù)字

isxdigit() 檢查是否為十六進制數(shù)字表示的有效字符

isspace() 檢查是否為空格類型字符

iscntrl() 檢查是否為控制字符

ispunct() 檢查是否為標點符號

isalnum() 檢查是否為字母和數(shù)字

isprint() 檢查是否是可打印字符

isgraph() 檢查是否是圖形字符，等效于 isalnum() | ispunct()

如何看c語言標準庫函數(shù)的源代碼?

很遺憾,標準庫中的函數(shù)結(jié)合了系統(tǒng),硬件等的綜合能力,是比較近機器的功能實現(xiàn),所以大部分是用匯編完成的,而且已經(jīng)導入到了lib和dll里了,就是說,他們已經(jīng)被編譯好了,似乎沒有代碼的存在了.

能看到的也只有dll中有多少函數(shù)被共享.

第三方可能都是dll,因為上面也說了,dll是編譯好的,只能看到成品,就可以隱藏代碼,保護自己的知識產(chǎn)權(quán),同時也是病毒的歸宿...... 當然,除了DLL的確還存在一種東西,插件程序~~~

C 語言標準庫函數(shù)

C語言標準庫函數(shù)

標準io函數(shù)

Standard C I/O

clearerr() clears errors

fclose() close a file

feof() true if at the end-of-file

ferror() checks for a file error

fflush() writes the contents of the output buffer

fgetc() get a character from a stream

fgetpos() get the file position indicator

fgets() get a string of characters from a stream

fopen() open a file

fprintf() print formatted output to a file

fputc() write a character to a file

fputs() write a string to a file

fread() read from a file

freopen() open an existing stream with a different name

fscanf() read formatted input from a file

fseek() move to a specific location in a file

fsetpos() move to a specific location in a file

ftell() returns the current file position indicator

fwrite() write to a file

getc() read a character from a file

getchar() read a character from STDIN

gets() read a string from STDIN

perror() displays a string version of the current error to STDERR

printf() write formatted output to STDOUT

putc() write a character to a stream

putchar() write a character to STDOUT

puts() write a string to STDOUT

remove() erase a file

rename() rename a file

rewind() move the file position indicator to the beginning of a file

scanf() read formatted input from STDIN

setbuf() set the buffer for a specific stream

setvbuf() set the buffer and size for a specific stream

sprintf() write formatted output to a buffer

sscanf() read formatted input from a buffer

tmpfile() return a pointer to a temporary file

tmpnam() return a unique filename

ungetc() puts a character back into a stream

vprintf, vfprintf, vsprintf write formatted output with variable argument lists

標準字符/字符串處理函數(shù)

atof() converts a string to a double

atoi() converts a string to an integer

atol() converts a string to a long

isalnum() true if alphanumeric

isalpha() true if alphabetic

iscntrl() true if control character

isdigit() true if digit

isgraph() true if a graphical character

islower() true if lowercase

isprint() true if a printing character

ispunct() true if punctuation

isspace() true if space

isupper() true if uppercase character

isxdigit() true if a hexidecimal character

memchr() searches an array for the first occurance of a character

memcmp() compares two buffers

memcpy() copies one buffer to another

memmove() moves one buffer to another

memset() fills a buffer with a character

strcat() concatenates two strings

strchr() finds the first occurance of a character in a string

strcmp() compares two strings

strcoll() compares two strings in accordance to the current locale

strcpy() copies one string to another

strcspn() searches one string for any characters in another

strerror() returns a text version of a given error code

strlen() returns the length of a given string

strncat() concatenates a certain amount of characters of two strings

strncmp() compares a certain amount of characters of two strings

strncpy() copies a certain amount of characters from one string to another

strpbrk() finds the first location of any character in one string, in another string

strrchr() finds the last occurance of a character in a string

strspn() returns the length of a substring of characters of a string

strstr() finds the first occurance of a substring of characters

strtod() converts a string to a double

strtok() finds the next token in a string

strtol() converts a string to a long

strtoul() converts a string to an unsigned long

strxfrm() converts a substring so that it can be used by string comparison functions

tolower() converts a character to lowercase

toupper() converts a character to uppercase

標準數(shù)學函數(shù)

abs() absolute value

acos() arc cosine

asin() arc sine

atan() arc tangent

atan2() arc tangent, using signs to determine quadrants

ceil() the smallest integer not less than a certain value

cos() cosine

cosh() hyperbolic cosine

div() returns the quotient and remainder of a division

exp() returns "e" raised to a given power

fabs() absolute value for floating-point numbers

floor() returns the largest integer not greater than a given value

fmod() returns the remainder of a division

frexp() decomposes a number into scientific notation

labs() absolute value for long integers

ldexp() computes a number in scientific notation

ldiv() returns the quotient and remainder of a division, in long integer form

log() natural logarithm

log10() natural logarithm, in base 10

modf() decomposes a number into integer and fractional parts

pow() returns a given number raised to another number

sin() sine

sinh() hyperbolic sine

sqrt() square root

tan() tangent

tanh() hyperbolic tangent

標準時間/日期函數(shù)

asctime() a textual version of the time

clock() returns the amount of time that the program has been running

ctime() returns a specifically formatted version of the time

difftime() the difference between two times

gmtime() returns a pointer to the current Greenwich Mean Time

localtime() returns a pointer to the current time

mktime() returns the calendar version of a given time

strftime() returns individual elements of the date and time

time() returns the current calendar time of the system

標準內(nèi)存管理函數(shù)

calloc() allocates a two-dimensional chunk of memory

free() makes memory available for future allocation

malloc() allocates memory

realloc() changes the size of previously allocated memory

其它標準函數(shù)

abort() stops the program

assert() stops the program if an expression isn';t true

atexit() sets a function to be called when the program exits

bsearch() perform a binary search

exit() stop the program

getenv() get enviornment information about a variable

longjmp() start execution at a certain point in the program

qsort() perform a quicksort

raise() send a signal to the program

rand() returns a pseudorandom number

setjmp() set execution to start at a certain point

signal() register a function as a signal handler

srand() initialize the random number generator

system() perform a system call

va_arg() use variable length parameter lists

求C語言標準函數(shù)庫的源代碼

標準庫只是定義接口，具體怎么實現(xiàn)就得看操作系統(tǒng)，你說win下和linux下這些函數(shù)的實現(xiàn)會一樣嗎。當然不一樣，看這些學源碼，不如看看c標準，c89或c99.

那可以看內(nèi)核，看系統(tǒng)調(diào)用是怎么樣實現(xiàn)的，你說的那些都是基于系統(tǒng)調(diào)用的

在C語言里，關(guān)于庫函數(shù)中各種數(shù)學函數(shù)的代碼。

你說的就是庫函數(shù)的源碼，也就是glibc，源碼在可以下到，比如下載，打開后就可以看到你需要的各種庫的具體實現(xiàn)代碼，比如在string中的strcat.c中就有

char?*strcat?(dest,?src)

char?*dest;

const?char?*src;

{

char?*s1?=?dest;

const?char?*s2?=?src;

reg_char?c;

/*?Find?the?end?of?the?string.??*/

do

c?=?*s1++;

while?(c?!=?'\0');

/*?Make?S1?point?before?the?next?character,?so?we?can?increment

it?while?memory?is?read?(wins?on?pipelined?cpus).??*/

s1?-=?2;

do

{

c?=?*s2++;

*++s1?=?c;

}

while?(c?!=?'\0');

return?dest;

}

本文標題：c語言標準函數(shù)庫代碼,c標準庫函數(shù)源代碼
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