diff --git a/src/header/monetary/cbindgen.toml b/src/header/monetary/cbindgen.toml
index 59294e84c5..003cbd5026 100644
--- a/src/header/monetary/cbindgen.toml
+++ b/src/header/monetary/cbindgen.toml
@@ -15,6 +15,7 @@ language = "C"
 style = "tag"
 no_includes = true
 cpp_compat = true
+usize_is_size_t = true
 
 [enum]
 prefix_with_name = true
diff --git a/src/header/monetary/strfmon.rs b/src/header/monetary/strfmon.rs
index ac436d4e9a..c0f380604e 100644
--- a/src/header/monetary/strfmon.rs
+++ b/src/header/monetary/strfmon.rs
@@ -1,4 +1,4 @@
-use crate::platform::types::c_char;
+use crate::platform::types::{c_char, size_t, ssize_t};
 
 use super::{DEFAULT_MONETARY, FormatFlags, LocaleMonetaryInfo, apply_grouping};
 use alloc::string::{String, ToString};
@@ -17,10 +17,10 @@ use libm::{fabs, pow, round, trunc};
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn strfmon(
     s: *mut c_char,        // Output buffer
-    maxsize: usize,        // Maximum size of the buffer
+    maxsize: size_t,       // Maximum size of the buffer
     format: *const c_char, // Format string
     mut args: ...          // Variadic arguments for monetary values
-) -> isize {
+) -> ssize_t {
     // Validate input pointers and buffer size
     if s.is_null() || format.is_null() || maxsize == 0 {
         return -1; // Invalid input
@@ -151,7 +151,7 @@ pub unsafe extern "C" fn strfmon(
         return -1; // Buffer overflow
     }
     buffer[pos] = 0; // Null-terminate the buffer
-    pos as isize // Return the number of characters written
+    pos as ssize_t // Return the number of characters written
 }
 
 /// Formats a monetary value into the given `buffer` using locale-specific rules