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  1. #include <iostream>
  2. #include <fstream>
  3. #include <sstream>
  4. #include <sys/types.h>
  5. #include <unistd.h>
  6. #include <cstring>   // for strlen
  7. using namespace std;
  8.  
  9. const int size = 8192;  // bigger buffer for many environment variables
  10.  
  11. int main() {
  12.     // Build the /proc/<pid>/environ path
  13.     ostringstream oss;
  14.     oss << "/proc/" << getpid() << "/environ";
  15.     cout << "Reading from file: " << oss.str() << endl;
  16.  
  17.     static char buffer[size] = {0};
  18.  
  19.     // Open environ in binary mode
  20.     ifstream i_file(oss.str().c_str(), ios::in | ios::binary);
  21.     if (!i_file) {
  22.         cerr << "Error: could not open " << oss.str() << endl;
  23.         return 1;
  24.     }
  25.  
  26.     // Read environment variables
  27.     i_file.read(buffer, size);
  28.  
  29.     // Walk through environment variables (null-separated)
  30.     char *p = buffer;
  31.     do {
  32.         cout << "[" << p << "]" << endl;
  33.         p += strlen(p) + 1;
  34.     } while (*p);
  35.  
  36.     return 0;
  37. }
Success #stdin #stdout 0.01s 5292KB
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stdin
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stdout
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Reading from file: /proc/3120129/environ
[PWD=/home/9KNm75]
[TMPDIR_GLOBAL=/tmp/]
[HOME=/home/9KNm75]
[LANG=en_US.UTF-8]
[TMPDIR=/tmp/VZn1Ed]
[WORKSPACE=/tmp/]
[SHLVL=0]
[PATH=/usr/local/bin:/usr/bin:/bin]
https://ideone.com/fkx4mG
language:
C++14 (gcc 8.3)
created:
4 days ago
visibility:
public

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