Recent questions tagged C

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If I have a C file like below, what is the difference between i and j? #include <stdio.h> #include <stdlib. ... () { //Some implementation } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - practical examples use dup or dup2

I know what dup / dup2 does, but I have no idea when it would be used. Any practical examples? Thanks. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Are GCC and Clang parsers really handwritten?

It seems that GCC and LLVM-Clang are using handwritten recursive descent parsers, and not machine generated, Bison- ... blog on this topic here See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - srand function is returning same values

Hey guys take a look at this program. /* The craps game, KN king page 218 */ #include <stdio.h> #include <time ... and run it to see what i mean See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why is a condition like (0 < a < 5) always true?

I implemented the following program in C #include <stdio.h> int main() { int a = 10 ; if(0 < a < 5) ... the condition 0<a<5 always return true? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - why does GCC __builtin_prefetch not improve performance?

I'm writing a program to analyze a graph of social network. It means the program needs a lot of random memory ... Xeon E5-4620. Thanks, Da See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - SegFault after scanf?

#include <stdio.h> #define TimeConverter 60 #define TempFormula time * time * 4 / time + 2 - 20 double ... segmentation fault when after scanf? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Do I really need malloc?

I understand that malloc is used to dynamically allocate memory. In my code, I have the following function that I ... I am declaring this array? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - printf not printing to screen

If I try to run the following simple code under Cygwin on Windows 7, #include <stdio.h> int main() { ... This works perfectly well under MinGW. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is the purpose of the div() library function?

When C has the / operator to divide two numbers, what is the purpose of having the div() library function? Is there ... t be used but div() can? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - isalpha() giving an assertion

I have a C code in which I am using standard library function isalpha() in ctype.h, This is on Visual Studio ... want to be able to neglect it. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - gcc failing to warn of uninitialized variable

The following code has a variable that may be uninitialized. It seems that gcc should be generating a ... report the uninitialized variable? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Using an anonymous struct vs a named struct with typedef

When should one of the following statements be used over the other? typedef struct Foo { int a; } Bar; and ... one be used over the other. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Pointers - Difference between Array and Pointer

What is the difference between a, &a and the address of first element a[0]? Similarly p is a pointer to an ... and the value pointed by p 5 See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Need to know when no data appears between two token separators using strtok()

I am trying to tokenize a string but I need to know exactly when no data is seen between two tokens. e.g when ... , it should be recorded as is. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How can I multiply 64 bit operands and get 128 bit result portably?

For x64 I can use this: { uint64_t hi, lo; // hi,lo = 64bit x 64bit multiply of c[0] and b[0] ... portably. For instance to work on x86. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - how to call function in executable from my library?

I have an executable and a dynamic library (.so). The library exports some symbols and executable calls it successfully. ... how can i fix it? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - undefined reference to `strlwr'

My code is like a text compressor, reading normal text and turns into numbers, every word has a number. It compiles ... } .... //main continues See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Kernel zeroes memory?

I am using Debian squeeze and have noticed that memory is always zeroed. Is this new in linux distributions ? ... that always zero memory ? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to print the address of a function?

I let gcc compile the following example using -Wall -pedantic: #include <stdio.h> int main(void) { printf(" ... printing a function's address? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Are there any platforms where using structure copy on an fd_set (for select() or pselect()) causes problems?

The select() and pselect() system calls modify their arguments (the 'fd_set *' arguments), so the input value ... it is not already available. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is the simplest way to write to stdout in binary mode?

I've been trying to figure out the best way to write binary data to stdout from a C program. It works ... and writing to stdout using fwrite. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to prevent system hang before watchdog timer task kicks in

We are using an ARM AM1808 based Embedded System with an rtos and a File System. We are using C language. ... board caused by some while loop. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Pass integer value through pthread_create

I simply want to pass the value of an integer to a thread. How can I do that? I tried: int i; ... different size [-Wpointer-to-int-cast] See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Bitwise '&' operator

I am lacking some basic understanding in bitwise '&' operator. 5 = 101 4 = 100 So why the output of the below if ... if(5&4) printf("Yes "); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Dynamic String Input - using scanf("%as")

I am trying to read input using scanf and storing into char * dynamically as specified by GCC manual, But it is ... free(string); //some code } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Please Explain Comma Operator in this Program

Please explain me the output of this program: int main() { int a,b,c,d; a=10; b=20; c=a,b; ... compiled and ran the program using Code Blocks. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why does gcc use movl instead of push to pass function args?

pay attention to this code : #include <stdio.h> void a(int a, int b, int c) { char buffer1[5]; ... it happen? what's difference between them? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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