我的fstream总是失败

请大家帮忙，我有以下小小的snip代码来测试fsteam，但它总是失败，而且我的代码后面跟着strace文件。它在unix中工作，但不在linux中。感谢您的帮助。我的fstream总是失败

#include <fstream.h> 
#include <iostream.h> 

using namespace std; 

int main() { 

     fstream filestr; 

     filestr.open ("test.txt",ios::out | ios::in | ios::app); 
     if(filestr.bad()) 
     {   
       cout << "Bad input." << endl; 
     }   
     if(filestr.fail()) 
     {   
       cout << "Open failed." << endl; 
     }  
     filestr << " dsgesvsvds"; 

     filestr.close(); 

     return 0; 
}

execve("./a.out", ["./a.out"], [/* 83 vars */]) = 0 
brk(0)         = 0x10754000 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8cf1e9d000 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8cf1e9e000 
access("/etc/ld.so.preload", R_OK)  = -1 ENOENT (No such file or directory) 
open("tls/x86_64/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("tls/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("x86_64/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("libstdc++.so.6", O_RDONLY)  = -1 ENOENT (No such file or directory) 
open("/products/oracle/11.2.0/client/lib/tls/x86_64/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
stat("/products/oracle/11.2.0/client/lib/tls/x86_64", 0x7fffd262c040) = -1 ENOENT (No such file or directory) 
open("/products/oracle/11.2.0/client/lib/tls/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
stat("/products/oracle/11.2.0/client/lib/tls", 0x7fffd262c040) = -1 ENOENT (No such file or directory) 
open("/products/oracle/11.2.0/client/lib/x86_64/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
stat("/products/oracle/11.2.0/client/lib/x86_64", 0x7fffd262c040) = -1 ENOENT (No such file or directory) 
open("/products/oracle/11.2.0/client/lib/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
stat("/products/oracle/11.2.0/client/lib", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 
open("/roscodev/rosco/bin/tls/x86_64/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
stat("/roscodev/rosco/bin/tls/x86_64", 0x7fffd262c040) = -1 ENOENT (No such file or directory) 
open("/roscodev/rosco/bin/tls/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
stat("/roscodev/rosco/bin/tls", 0x7fffd262c040) = -1 ENOENT (No such file or directory) 
open("/roscodev/rosco/bin/x86_64/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
stat("/roscodev/rosco/bin/x86_64", 0x7fffd262c040) = -1 ENOENT (No such file or directory) 
open("/roscodev/rosco/bin/libstdc++.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
stat("/roscodev/rosco/bin", {st_mode=S_IFDIR|0775, st_size=12288, ...}) = 0 
open("/etc/ld.so.cache", O_RDONLY)  = 3 
fstat(3, {st_mode=S_IFREG|0644, st_size=80518, ...}) = 0 
mmap(NULL, 80518, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2b8cf1e9f000 
close(3)        = 0 
open("/usr/lib64/libstdc++.so.6", O_RDONLY) = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0000\364\304\3528\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0755, st_size=976312, ...}) = 0 
mmap(0x38eac00000, 3145600, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x38eac00000 
mprotect(0x38eace6000, 2093056, PROT_NONE) = 0 
mmap(0x38eaee5000, 36864, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xe5000) = 0x38eaee5000 
mmap(0x38eaeee000, 73600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x38eaeee000 
close(3)        = 0 
open("tls/x86_64/libm.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("tls/libm.so.6", O_RDONLY)   = -1 ENOENT (No such file or directory) 
open("x86_64/libm.so.6", O_RDONLY)  = -1 ENOENT (No such file or directory) 
open("libm.so.6", O_RDONLY)    = -1 ENOENT (No such file or directory) 
open("/products/oracle/11.2.0/client/lib/libm.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("/roscodev/rosco/bin/libm.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("/lib64/libm.so.6", O_RDONLY)  = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`>\200\3438\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0755, st_size=615136, ...}) = 0 
mmap(0x38e3800000, 2629848, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x38e3800000 
mprotect(0x38e3882000, 2093056, PROT_NONE) = 0 
mmap(0x38e3a81000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x81000) = 0x38e3a81000 
close(3)        = 0 
open("tls/x86_64/libgcc_s.so.1", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("tls/libgcc_s.so.1", O_RDONLY)  = -1 ENOENT (No such file or directory) 
open("x86_64/libgcc_s.so.1", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("libgcc_s.so.1", O_RDONLY)   = -1 ENOENT (No such file or directory) 
open("/products/oracle/11.2.0/client/lib/libgcc_s.so.1", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("/roscodev/rosco/bin/libgcc_s.so.1", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("/lib64/libgcc_s.so.1", O_RDONLY) = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\36\200\3468\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0755, st_size=58400, ...}) = 0 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8cf1eb3000 
mmap(0x38e6800000, 2151784, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x38e6800000 
mprotect(0x38e680d000, 2097152, PROT_NONE) = 0 
mmap(0x38e6a0d000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xd000) = 0x38e6a0d000 
close(3)        = 0 
open("tls/x86_64/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("tls/libc.so.6", O_RDONLY)   = -1 ENOENT (No such file or directory) 
open("x86_64/libc.so.6", O_RDONLY)  = -1 ENOENT (No such file or directory) 
open("libc.so.6", O_RDONLY)    = -1 ENOENT (No such file or directory) 
open("/products/oracle/11.2.0/client/lib/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("/roscodev/rosco/bin/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) 
open("/lib64/libc.so.6", O_RDONLY)  = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\220\332\1\3438\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0755, st_size=1722304, ...}) = 0 
mmap(0x38e3000000, 3502424, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x38e3000000 
mprotect(0x38e314e000, 2097152, PROT_NONE) = 0 
mmap(0x38e334e000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x14e000) = 0x38e334e000 
mmap(0x38e3353000, 16728, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x38e3353000 
close(3)        = 0 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8cf1eb4000 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8cf1eb5000 
arch_prctl(ARCH_SET_FS, 0x2b8cf1eb4bf0) = 0 
mprotect(0x38e334e000, 16384, PROT_READ) = 0 
mprotect(0x38e3a81000, 4096, PROT_READ) = 0 
mprotect(0x38eaee5000, 24576, PROT_READ) = 0 
mprotect(0x38e2e1b000, 4096, PROT_READ) = 0 
munmap(0x2b8cf1e9f000, 80518)   = 0 
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8cf1e9f000 
write(1, "Open failed.\n", 13Open failed. 
)   = 13 
exit_group(0)       = ?

来源

2011-03-10 user630675

#include <fstream.h> 
#include <iostream.h>

应该

#include <fstream> 
#include <iostream>

来源

2011-03-10 21:04:25 fouronnes

我明白了：ios :: in和ios :: out一起引发了这个问题，所以我把ios :: in带出来，它变成了 filestr.open（“test.txt”，ios :: out | ios :: app）; 然后它工作正常。但为什么?????? – user630675 2011-03-12 01:00:42

哦。也许是因为'fstream'已经用于输入和输出了。 'ifstream'仅用于输入，'ofstream'仅用于输出。你应该尝试设置'ios :: out'和'ios :: in' – fouronnes 2011-03-12 11:47:17

您正在使用C++，和标准的头没有.h扩展类似于C的因此，您需要#include<fstream>和<iostream>。如果我纠正你的#include错误（ - 无.H应该#include <fstream>和#include <iostream>）

来源

2011-03-10 21:05:55

你的代码工作得很好，我的Ubuntu 9.10下。但我怀疑这不是你的问题，因为这会导致编译错误。可能你有权限错误？如果我创建test.txt并删除写入权限，则会显示“打开失败”。信息。

来源

2011-03-10 21:10:37

谢谢你。我在redhat linux下试用了没有.h的版本，对我也失败了。我还尝试过在运行之前先触摸一个文件，没有运气。希望有人能给我一些见解。 – user630675 2011-03-11 00:05:01

我在修正头文件后，在Windows8.1上的DevC++中运行它，它工作正常。

来源

2015-05-03 13:33:14 Aditya

我的fstream总是失败

回答

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