zip_fopen,
    zip_fopen_index — open file
    in zip archive for reading
#include
  <zip.h>
zip_file_t *
  
  zip_fopen(zip_t
    *archive, const char
    *fname, zip_flags_t
    flags);
zip_file_t *
  
  zip_fopen_index(zip_t
    *archive, zip_uint64_t
    index, zip_flags_t
    flags);
Upon successful completion, a struct
    zip_file pointer is returned. Otherwise, NULL
    is returned and the error code in archive is set to
    indicate the error.
  - [ZIP_ER_CHANGED]
- The file data has been changed and the data source does not support
      rereading data.
- [ZIP_ER_COMPNOTSUPP]
- The compression method used is not supported.
- [ZIP_ER_ENCRNOTSUPP]
- The encryption method used is not supported.
- [ZIP_ER_MEMORY]
- Required memory could not be allocated.
- [ZIP_ER_NOPASSWD]
- The file is encrypted, but no password has been provided.
- [ZIP_ER_READ]
- A file read error occurred.
- [ZIP_ER_SEEK]
- A file seek error occurred.
- [ZIP_ER_WRONGPASSWD]
- The provided password does not match the password used for encryption.
      Note that some incorrect passwords are not detected by the check done by
      zip_fopen().
- [ZIP_ER_ZLIB]
- Initializing the zlib stream failed.
The function zip_fopen() may also fail and
    set zip_err for any of the errors specified for the
    routine
    zip_name_locate(3).
The function zip_fopen_index() may also
    fail with ZIP_ER_INVAL if
    index is invalid.
zip_fopen() and
    zip_fopen_index() were added in libzip 1.0.