Recent questions tagged C

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This is going to be some what of a newbie question but I was trying to work on a small exercise in ... information before it can be answered. 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 forking my process cause the file to be read infinitely

I've boiled down my entire program to a short main that replicates the issue, so forgive me for it not making ... lines of words it will not. 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 - Declare and initialize pointer concisely (i. e. pointer to int)

Given pointers to char, one can do the following: char *s = "data"; As far as I understand, a pointer ... pointers at all (joke) or something? 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 - Programmatically retrieving the absolute path of an OS X command-line app

On Linux, an application can easily get its absolute path by querying /proc/self/exe. On FreeBSD, it's more ... have seen in the wild.) 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 - I have Python on my Ubuntu system, but gcc can't find Python.h

I am on a school computer, so I can't install anything. I am trying to create C code which can be run ... the computer actually has Python.h? 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 are .a and .so files?

I'm currently trying to port a C application to AIX and am getting confused. What are .a and .so ... used when building/running an application? 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 - Variadic macro trick

What's the trick to create a variadic macro FOO(a1, a2, a3,..., an) such that it expands to FOOn(a1, a2, ... there is but I couldn't find 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 - Increasing limit of FD_SETSIZE and select

I want to increase FD_SETSIZE macro value for my system. Is there any way to increase FD_SETSIZE so select will not fail 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 - Unexpected output when printing directly to text video memory

I am developing a kernel in C and created something to print on screen on video memory. I expected that the first byte ... fr os-image *.bin *.o 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 - main() functions return value?

Anyone please tell me where the main() function of the 'C' language returns its value? 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 int for character types when comparing with EOF

Quoting from Kernighan and Ritchie's 'The C Programming Language' Page 16 - #include<stdio.h> main() { int c; ... in 2's complement notation)? 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 - No defined type of a function parameter defaults to int? Am I insane?

For some odd reason I was copying an example in another language of which does not use types, and forgot to ... outdated GCC port (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 - Is my fma() broken?

In using double fma(double x, double y, double z); I'd expect a non-zero d in the output lines below marked ... posix gcc version 5.3.0 (GCC) 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 wait() set status to 255 instead of the -1 exit status of the forked process?

I'm trying to return an integer value from a child process. However, if I use exit(1) I get 256 as the ... ). Is it supposed to be unsigned? 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 - Getting max value in a __m128i vector with SSE?

I have just started using SSE and I am confused how to get the maximum integer value (max) of a __m128i ... looking into the header file itself? See Question&Answers more detail:os...

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

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378 views

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c - Does Microsoft visual studio 2010 support c99?

I would like to know if Microsoft Visual Studio 2010 supports C99. If not, how can I use the standard types like intptr_t and uintptr_t? 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 - Casting a pointer does not produce an lvalue. Why?

After posting one of my most controversial answers here, I dare to ask a few questions and eventually fill ... when doing pointer arithmetic. See Question&Answers more detail:os...

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

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289 views

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c - OpenCV: how to force the image window to appear on top of other windows?

Using cvShowImage, one can easily show an image in OpenCV. However, how do you tell OpenCV to show the window on ... there another way to do 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 preprocessor - Changing a macro at runtime in C

I have a macro defined. But I need to change this value at run time depending on a condition. How can I implement this? 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 - Lookups on known set of integer keys

Gperf consistently underperforms a Judy array in my environment, and I'm wondering if there is another perfect hash ... that for now. :) See Question&Answers more detail:os...

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

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243 views

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c - How can I access a graphics card's output directly?

Do graphics cards typically write their output to some place in memory which I can access? Do I have to use ... read the output from 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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343 views

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c - strstr not functioning

Why does this particular piece of code return false on the strstr() if I input "test"? char input[100]; int ... seems to not work with fgets. See Question&Answers more detail:os...

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

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304 views

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c - signed and unsigned arithmetic implementation on x86

C language has signed and unsigned types like char and int. I am not sure, how it is implemented on ... emulated for the different case? See Question&Answers more detail:os...

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

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453 views

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c - Confusion regarding modification of const variable using pointers

Following example added confusion in my understanding. I'm unable to understand how is it possible to modify the ... value of local: 100 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 - Accesing a 2D array using a single pointer

There are tons of code like this one: #include <stdio.h> int main(void) { int a[2][2] = {{0, ... evaluated. Can someone explain this in detail? See Question&Answers more detail:os...

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

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281 views

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c - Is there a tool to know whether a value has an exact binary representation as a floating point variable?

My C API has a function that takes as input a double. Only 3 or 4 values are valid input, all ... representation as a floating point value? See Question&Answers more detail:os...

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

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481 views

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c - Access struct members as if they are a single array?

I have two structures, with values that should compute a pondered average, like this simplified version: typedef ... member? Thanks, Beco See Question&Answers more detail:os...

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

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938 views

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c - note: previous implicit declaration of ‘point_forward’ was here

I can't seem to get this recursive function to compile properly, and I'm not sure why. The code is ... declaration of point_forward' was 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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