Usually Function

String:

• strlen (const char *s) [http://www.gnu.org/software/libc/manual/html_node/String-Length.html]
• sprintf (workName, "tTcpWork%d", ix++);
  

Byte Manipulate:

• bzero (buffer,256)

File:

• read (sFd, buffer, 255);
• write (sFd, buffer, strlen (buffer))
  

Process:

• fork()
  

Input/Ouput:

• scanf /*Read is a token as yhou want*/
  

     int  scanf ( const char * format, ... );

• gets(char *); /* Read the the stdin and is a string*/
  

• fgets /*Read from the file */
  

  char * fgets ( char * str, int num, FILE * stream );

Notice: gets will generate dangerous problem, so can using the fgets.

http://dsewnr.blogspot.com/2007/05/c-gets.html

http://www.cplusplus.com/reference/clibrary/cstdio/scanf/

Forking

{{{

#include
void main(void) {
int pid, i;

pid = fork();

/*Child process the pid is zero at this */
if (pid ==0) {
printf("I am child and pid %d\n",getpid());
for (i=0; i < 44; i++) {
printf("I am chid and say %d\n", i);
}
}
else if (pid > 0) { /* Parent pid will use choild*/
printf("I am parent and pid %d\n",getpid());
for (i = 0; i < 40; i++) {
printf("I am parent process and say %d\n", i);
}
}
else if (pid < 0) {
printf ("Sorry, can't fork my self\n");
}
}


}}}

Reference:
http://forum.slime.com.tw/thread190607.html

Socket programing

Sample

• http://www.linuxhowtos.org/C_C++/socket.htm
• http://www-kryo.desy.de/documents/vxWorks/V5.5/vxworks/netguide/c-sockets.html

Writing and function list
http://www.retran.com/beej/index.html

Precedence of the operators

Reference:
http://en.cppreference.com/w/cpp/language/operator_precedence
http://www.swansontec.com/sopc.html

perror

Goal: will show the error number corresponding to string

Sample:

標頭檔: #include

函式定義: void perror(const char *s);

說明

perror 會將錯誤值對應到的錯誤訊息列印到標準錯誤串流中。

範例

/*perror 將錯誤編碼轉誠文字*/ #include   int main() {     FILE *stream;      if((stream = fopen("open", "r")) == NULL){  perror("fopen");     }      return 0; }


Output:
fopen: No such file or directory

Data Type Change

atoi (asci to integer)

Reference:http://www.cplusplus.com/reference/clibrary/cstdlib/atoi/


atoi
function


int atoi ( const char * str );

Convert string to integer
Parses the C string str interpreting its content as an integral number, which is returned as an int value.

The function first discards as many whitespace characters as necessary until the first non-whitespace character is found. Then, starting from this character, takes an optional initial plus or minus sign followed by as many numerical digits as possible, and interprets them as a numerical value.

The string can contain additional characters after those that form the integral number, which are ignored and have no effect on the behavior of this function.

If the first sequence of non-whitespace characters in str is not a valid integral number, or if no such sequence exists because either str is empty or it contains only whitespace characters, no conversion is performed.

Data type

http://msdn.microsoft.com/en-us/library/s3f49ktz%28v=vs.80%29.aspx


Type Name Bytes Other Names Range of Values

int


4


signed


–2,147,483,648 to 2,147,483,647

unsigned int


4


unsigned


0 to 4,294,967,295

__int8


1


char


–128 to 127

unsigned __int8


1


unsigned char


0 to 255

__int16


2


short, short int, signed short int


–32,768 to 32,767

unsigned __int16


2


unsigned short, unsigned short int


0 to 65,535

__int32


4


signed, signed int, int


–2,147,483,648 to 2,147,483,647

unsigned __int32


4


unsigned, unsigned int


0 to 4,294,967,295

__int64


8


long long, signed long long


–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

unsigned __int64


8


unsigned long long


0 to 18,446,744,073,709,551,615

bool


1


none


false or true

char


1


none


–128 to 127 by default

0 to 255 when compiled with /J

signed char


1


none


–128 to 127

unsigned char


1


none


0 to 255

short


2


short int, signed short int


–32,768 to 32,767

unsigned short


2


unsigned short int


0 to 65,535

long


4


long int, signed long int


–2,147,483,648 to 2,147,483,647

unsigned long


4


unsigned long int


0 to 4,294,967,295

long long


8


none (but equivalent to __int64)


–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

unsigned long long


8


none (but equivalent to unsigned __int64)


0 to 18,446,744,073,709,551,615

enum


varies


none


See Remarks.

float


4


none


3.4E +/- 38 (7 digits)

double


8


none


1.7E +/- 308 (15 digits)

long double


same as double


none


same as double

wchar_t


2


__wchar_t


0 to 65,535